Word of Wisdom Foibles
In the following quotes, text bolding was added by me to highlight key words or phrases.
The LDS doctrine of "Word of Wisdom" is laid out in their scriptural text "Doctrine and Covenants" section 89. It declares that Wine and "Strong Drink" should be avoided. When first issued by Joseph Smith (the founder of Mormonism), this missive was merely a suggestion. Later - around the time of Prohibition in the United States - the LDS church leadership declared it to be a commandment of God, no longer a guideline to be followed, and that failure to follow it is now sinful.
(It is a part of LDS legend that the WoW came to be after Joseph's wife, Emma, complained about the mess left behind after meeting with his church leadership - tobacco stains, in particular. In the legend - which might even be found in teaching materials at  - Joseph had to ask God about this three times before he got a response; each of those times at Emma's behest, asking questions along the line of "Your God knows so much - what does he have to say about the mess you-all leave behind?")
From Doctrine and Covenants, section 20 (as of April 20, 2012):
38 The duty of the elders, priests, teachers, deacons, and members of the church of Christ—An apostle is an elder, and it is his calling to baptize; 39 And to ordain other elders, priests, teachers, and deacons; 40 And to administer bread and wine—the emblems of the flesh and blood of Christ— 41 And to confirm those who are baptized into the church, by the laying on of hands for the baptism of fire and the Holy Ghost, according to the scriptures; 42 And to teach, expound, exhort, baptize, and watch over the church; 43 And to confirm the church by the laying on of the hands, and the giving of the Holy Ghost; 44 And to take the lead of all meetings.
78 The manner of administering the wine—he shall take the cup also, and say: 79 O God, the Eternal Father, we ask thee in the name of thy Son, Jesus Christ, to bless and sanctify this wine to the souls of all those who drink of it, that they may do it in remembrance of the blood of thy Son, which was shed for them; that they may witness unto thee, O God, the Eternal Father, that they do always remember him, that they may have his Spirit to be with them. Amen.
From Doctrine and Covenants Section 27 (as of April 20, 2012):
Introduction: Revelation given to Joseph Smith the Prophet, at Harmony, Pennsylvania, August 1830 (see History of the Church, 1:106–8). In preparation for a religious service at which the sacrament of bread and wine was to be administered, Joseph set out to procure wine. He was met by a heavenly messenger and received this revelation, a portion of which was written at the time and the remainder in the September following. Water is now used instead of wine in the sacramental services of the Church. 1 Listen to the voice of Jesus Christ, your Lord, your God, and your Redeemer, whose word is quick and powerful. 2 For, behold, I say unto you, that it mattereth not what ye shall eat or what ye shall drink when ye partake of the sacrament, if it so be that ye do it with an eye single to my glory—remembering unto the Father my body which was laid down for you, and my blood which was shed for the remission of your sins. 3 Wherefore, a commandment I give unto you, that you shall not purchase wine neither strong drink of your enemies; 4 Wherefore, you shall partake of none except it is made new among you; yea, in this my Father’s kingdom which shall be built up on the earth.
5 Behold, this is wisdom in me; wherefore, marvel not, for the hour cometh that I will drink of the fruit of the vine with you on the earth,
(The charge of 'violating commandment by using water instead of wine' is countered by the text of verse 2.)