http://LDS.org/ensign/1986/05/happiness ... =happiness
Words such as reap, restored, and desire imply that happiness is a consequence, not a reward. We are restored to a state of happiness when we have chosen to live according to the plan of happiness. Our joy in God’s kingdom will be a natural extension of the happiness we cultivate in this life.
The doctrine is concisely summarized by Alma: “Behold, I say unto you, wickedness never was happiness.” (Alma 41:10; italics added.) If we are not pure, we would be miserable in the presence of God and Christ, who are by their very nature happy and joyful and cannot look upon sin with any allowance.
Our wise and loving Father in Heaven is concerned for the welfare of his children. He desires to see us happy. The very purpose of our lives can be defined in terms of happiness. The Prophet Joseph Smith said, “Happiness is the object and design of our existence; and will be the end thereof, if we pursue the path that leads to it.” (History of the Church, 5:134.)
These sorts of sentiments are frequently expressed in the church (of course that Joseph Smith quote is never given in context - he was trying to convince a young woman to be another of his plural wives).
Having said that, why do you suppose Mormons are the most unhappy group of people in America? They're the most depressed and have the most frequent thoughts of suicide.
Is Mormonism wickedness, and therefore the cause of great unhappiness? Or are Mormons themselves the most wicked group of people in America, and therefore the least happy? Or is it something else? What do you suppose the answer is? How can we help the Mormons to be more happy?