This post is less about what the LDS church teaches publicly or in writing, and more about what is often not publicly admitted to, whether still believed or not, and about some of the crazier things Mormons come to believe when embedded in Mormon culture. Though not categorized, some of these are doctrinal, others hearsay over the pulpit from apostles or leaders, and others adopted by more orthodox Mormons. (see also: Top 10 Mormon Beliefs that Contradict Christianity)
1. Polygamy is still doctrinal in heaven and included in LDS scripture. See D&C 132
2. Sports should not be played on Sunday
3. TV or movies should not be viewed on Sunday (except Church or "happy" media)
4. Children should not be allowed to play with friends on Sunday
5. Working on Sunday is strictly discouraged and really only not looked down on if you're an emergency response personnel, or other on-call emergency type jobs (doctors, police, firemen, nurses etc)
6. Rated R movies should be strictly avoided
7. 10% of your gross income (tithing) needs to be paid to the bishop/church before you pay for any other financial obligations, bills, food or other purchases
8. Coffee and tea are prohibited even though they aren't specifically referenced by doctrine
9. For some families, all caffeinated drinks and sodas are prohibited
10. If you have dark skin and convert to Mormonism, your skin will begin to lighten/whiten
11. You become a God/Goddess and are given powers to create your own worlds without number
12. You should not be alone in a room or car with a member of the opposite sex to "avoid even the appearance of evil"
13. Beer is prohibited even though it is scripturally allowed (D&C 89:17) "...and barley for all useful animals, and for mild drinks, as also other grain" Beer was openly consumed in Utah by Mormons until Prohibition made it unpopular and the practice ceased.
14. The Garden of Eden was in Missouri when Adam and Eve were kicked out
15. All saints are to return to Missouri before the final arrival of Jesus for the Second Coming. Some believe this exodus back to Missouri would be on foot.
16. Two LDS Elders or Missionaries will stand and protect the city of Jerusalem during Armageddon, as spoken of in Revelations and D&C 77:15
17. Native Americans are the descendants of the Lamanites spoken of in the Book of Mormon
18. The LDS Temple marriage is considered superior to all other religious marriage ceremonies and must be obtained if you want to be with your spouse in the after life. Not married in the temple? Too bad, no spouse/partner in the after life.
19. Love isn't as strong between couples and families who are not LDS
20. Follow the prophet or leaders even if you think they are wrong
21. Criticism of prophets or leaders will lead you towards apostasy
22. Don't use Ouija boards, face cards or tarot cards. They are of the devil.
23. The US Constitution will hang by a thread and be saved by LDS Elders before the 2nd coming
24. Women were discouraged from wearing pants up until the late '60s or '70s
25. 3 Nephites still rome the Earth from Christ's visit to the America's, blessed by Him to not experience death until his second coming
26. The moon will literally turn to blood during second coming crisis
27. Heavenly Mother/Goddess exists, but she/them are too sacred to discuss and cannot be worshiped or prayed to
28. Only Mormon's can go to the highest degree of heaven, which is why proxy ordinances are done in LDS temples for as many dead people as LDS Inc can get their hands on
29. Kids or babies who die before reaching 8 years old are perfect and automatically get into heaven
30. Missionaries can curse people by dusting their feet off as a witness to them rejecting the gospel
31. Satan has power over the oceans, lakes and rivers which is why LDS Missionaries are not allowed to swim
32. Satan can't read your thoughts so praying silently can help keep some of your secrets from him
33. Dating is strictly prohibited until you're 16 and then only group dating is allowed or encouraged until you can marry after your mission or marry a return missionary
34. Doctrinal polygamy gives the 1st wife authority to reject any prospects she doesn't like. This was never really practiced though.
35. Women who fail to marry in the temple during their life will be assigned a worthy spouse in the hereafter and likely as a sister wife with a harem of women
36. Black people bear the curse of Cain and were born black because they were less valiant in the pre-existence (pre-Earth life) and sat on the fence as to whether to follow Satan/Lucifer or Jesus
37. Cremation will make being resurrected harder, having to recollect all of your atoms/molecules from where ever they were spread
38. God the father is only one of millions or endless Gods who are all basically relatives, fathers, brothers, grand-gods and so forth to our own God. If we're worthy, we get to join the God club too.
39. From the polygamy days, a man had to have at least 2 wives to get into the highest degree of heaven
40. A woman's purpose in heaven is solely to birth endless babies to populate the worlds created by their husbands. Billions and billions of babies!
41. Gestation is still 9 months in heaven
42. You are better off dying trying to fend off a rapist than to survive as a victim of rape, your virginity forever stolen from you
43. Temple garments or underwear will protect you from physical harm or the grasp of Satan
44. Girls can only have one piercing in each ear. No piercings allowed by boys/men.
45. Tattoos are a big no-no and should never be allowed to defile your bodies. If you have tattoos when you convert, you may be encouraged to pay for laser removal at your own expense.
46. Flip-flops are not to be worn in the church building
47. All forms of birth control (condoms, pills, etc) are discouraged and the couple should allow as many children into their home as God decides to send them
48. The Earth was not created by God, but by Jesus and Michael/Adam as taught in the LDS Temple endowment ceremony
49. Secret hand shakes, keywords and signs are provided in the Temple endowment as passwords and keys to get back into heaven, like a kids club where only those with the secret passwords can get in
50. The church partners with Boy Scouts of America for the development of males but does not endorse nor partner with the Girl Scout programs or similar female development programs
51. The Holy Ghost is threatened or turned away by bars, clubs and "dirty" places so will not protect you or guide you if you choose to enter such filthy places
52. Mormon Garments must be worn day and night, only removed for sex, showering and some sporting activities
53. Women must wear their bras and panties over their garments, as the garment should be the layer closest to the skin for maximum protection
54. If you're not a Mormon, or are unworthy without a temple recommend, you get excluded from the Temple wedding ceremony of loved ones, kids, siblings or best friends
55. Mormon's do feel there is something special about them, or that they are better than non-mormons. Having the ultimate "truth" does that to people.
56. Masturbation is a sexual sin/transgression and seen as cheating on your existing or future spouse
57. Sexual transgression is a sin next to murder in God's eyes
58. Jesus atoned for our sins in the Garden of Gethsemane, not on the cross
59. Jesus wasn't born of a virgin. God had natural sex with Mary to impregnate Jesus
60. You can't get into heaven without Joseph Smith's permission
61. You can visit loved ones in lower kingdoms, but you cannot visit higher kingdoms of heaven if you didn't merit it yourself, though they can visit you (see D&C 76)
62. You can tell the difference between a good angel, bad angel or resurrected being by their willingness or ability to shake your hand
63. No rainbows shall appear during the year before Jesus' second coming
64. If you've had a sex change, you cannot ever hold any callings/jobs in the church and only get baptized at the express permission of the First Presidency/prophet
65. Role playing games, like D&D, are also evil
66. Dinosaur fossils are to test our faith, and likely came from matter left over from past destroyed planets that were used/recycled to create Earth
67. When a prophet or leader errors, it was because he was acting as a man and not as a prophet. There's no indication until after the fact as to whether he was acting as one or the other, so you should always presume he's acting as prophet until proven otherwise
68. Free agency and choice is revered, but don't make the wrong choice or we will judge, look down on and guilt you until you either stop making said wrong choices
69. Once the prophet or brethren have spoken, the thinking has been done. Don't question it.
70. When someone leaves the church, it is God's way of separating the wheat (good mormons) from the chaff (bad, evil apostates)
71. Jesus was supposed to come in the year 2000, that is until he didn't
72. God is a resurrected, extra terrestrial, exalted human male who lives on a planet near a star called Kolob. See Book of Abraham, chapter 3 in Pearl of Great Price
73. Even though Jesus had a beard, we aren't allowed to have facial hair while attending the Lord's University, BYU, and are discouraged or flat out not allowed to have facial hair in high up leadership positions, despite early leaders all having beards
74. The LDS Temple questions somewhat encourage the shunning or disassociating with anyone who is anti, apostate, or against the church. This may include family members, close relatives or best friends if they end up leaving the church.
75. The "Inspired" Joseph Smith translation of the bible is more correct than the KJV
76. Joseph Smith's money digging and glass looking were actually God's way of preparing him for his role as a prophet and revelator.
77. Our dead relatives and angel friends can see us when we sin, and so even when alone, it is not safe to masturbate or do anything "bad".
78. The Holy Ghost goes to bed at midnight, so all dates, sleepovers, or other activities by youth or single people need to end by midnight or else you won't have protection or guidance against the temptations of the devil
79. Hoard enough food, water and fuel to survive 3-12 months or more
80. Women must wear modest clothing that extends to the floor while kneeling down (shorts, skirts etc) and that covers the shoulders and upper arms, no revealing of the midrift, no bikini swim suits, no tank tops, no spaghetti straps etc
81. Satan's real name in the Pre-existence is Lucifer, even though that name is only used once in the Old Testament
82. The ancient Jews were the only people who would kill Christ and therefore the most wicked people in the universe
83. So long as the US/America's stay righteous, aka, primarily Christian and God fearing, they will not be attacked by foreign powers or enemies (stems from the tradition laid out in the Book of Mormon that righteousness equals protection from enemies by God etc).
84. The Earth is a living entity that must also go through ordinances, death and exaltation. The Flood of Noah was the Earth's baptism. The fire and burning at the 2nd coming will be the baptism by fire and immediately after, exaltation to a perfect sphere of glass
85. The Earth was once in orbit around Kolob, but was expelled when Adam fell from the Garden of Eden. It will again return to that orbit after the millennium.
86. If you don't make it to the highest degree of the Celestial Kingdom, you will be gender-less in the after life. No sex or sex urges for you in the Terrestrial and Telestial kingdoms.
87. When people leave the church and can't leave it alone (despite being psychologically and emotionally damaged by it), it is called "kicking against the pricks", and is fulfillment of prophesy.
88. There are people living on the moon. LINK They dress much like Quakers and they are tall, many standing seven feet tall or more. One day we will send missionaries to teach them the gospel. There are also people living on the sun. Journal of Discourses, Vol. 13, p. 217
89. Brigham Young (2nd LDS prophet) taught that Adam was the literal God of the Earth and Earth's family
90. If you serve valiantly as a missionary, you'll be blessed with a beautiful and righteous spouse when you return
91. If you hold your right arm to the square and invoke the power of the priesthood, you can cast out devils, divert floods and lava flows, and baptize others
92. Women covenant in the temple to "observe and keep the law of the Lord and hearken unto the counsel of your husband as he hearkens unto the counsel of the Father"
93. All covenant in the temple "to sacrifice all that we possess, even our own lives if necessary, in sustaining and defending the Kingdom of God"
94. We covenant to "avoid all lightmindedness, loud laughter, evil speaking of the Lord's anointed, the taking of the name of God in vain, and every other unholy and impure practice"
95. More, we covenant in temples to "accept the Law of Consecration as contained in theDoctrine and Covenants, in that you do consecrate yourselves, your time, talents, and everything with which the Lord has blessed you, or with which he may bless you, to the Church of Jesus Christ of Latter-day Saints, for the building up of the Kingdom of God on the earth and for the establishment of Zion"
96. Garments represent the garment God/Jesus made and gave to Adam when he discovered his nakedness in the Garden of Eden
97. Women are most valued when in the home, rearing children and taking care of domestic affairs (laundry, dishes, house cleaning, etc)
98. In the temple marriage covenant/ceremony, women "give [themselves] to [their husband] to be his lawful and wedded wife" and men "receive her unto [himself] to be [his] lawful and wedded wife for time and all eternity"
99. If a widow remarries a man for time only, and bears him children, those children will belong to her first and sealed husband in the eternities
100. Before a woman can remarry in the temple for eternity, she must first get a temple sealing annulment, which can only come at the approval of the First Presidency, and will likely not be allowed if the first husband is deceased
101. Women were at one point allowed to give blessings by the laying on of hands, but that practice was ended when they were found to be more successful at healing than the priesthood holding men
For more discussion on these and other beliefs, please follow this thread in the forum: The nonpublic mormon beliefs not included on mormonbeliefs.org