...Men are that they might have joy. 2 Ne 25:5
Our Heavenly Father sent us to earth with the commission to learn to be like Him. One of the ways that we can be like God is to be happy because God is happy. True happiness includes feelings of peace, joy, gratitude, and pure love. Such feelings are inspired by the Holy Ghost.
Happiness is a gift that comes from striving to live in accordance with Christ's teachings. God's promises can be trusted, and he has promised happiness to those who follow him: "Happy is he that hath the God of Jacob for his help, whose hope is in the Lord his God" Ps 146:5 "Learn of me, and listen to my words; walk in the meekness of my Spirit, and you shall have peace in me." D&C 19:23 "And the work of righteousness shall be peace; and the effect of righteousness quietness and assurance for ever." Isa 32:17 "If ye know these things, happy are ye if ye do them." John 13:17 "he who doeth the works of righteousness shall receive his reward, even peace in this world, and eternal life in the world to come." D&C 59:23
There is a difference between the happiness that comes from God and the fleeting happiness that comes from following our own wills. "Ye have sought all the days of your lives for that which ye could not obtain; and ye have sought for happiness in doing iniquity, which thing is contrary to the nature of that righteousness which is in our great and Eternal Head." Hel 13:38 "Do not suppose...that ye shall be restored from sin to happiness. Behold, I say unto you, wickedness never was happiness." Alma 41:10
One of the happiest civilizations in history was found among the Nephite and Lamanite people in the ancient Americas who were converted to Christ after his resurrection and his visit among them:
"They had all things common among them; therefore there were not rich and poor, bond and free, but they were all made free, and partakers of the heavenly gift. And they were married, and given in marriage, and were blessed according to the multitude of the promises which the Lord had made unto them. And they did not walk any more after the performances and ordinances of the law of Moses; but they did walk after the commandments which they had received from their Lord and their God, continuing in fasting and prayer, and in meeting together oft both to pray and to hear the word of the Lord. And it came to pass that there was no contention among all the people, in all the land; but there were mighty miracles wrought among the disciples of Jesus. They did heal the sick, and raise the dead, and cause the lame to walk, and the blind to receive their sight, and the deaf to hear And it came to pass that there was no contention in the land, because of the love of God which did dwell in the hearts of the people. And there were no envyings, nor strifes, nor tumults, nor whoredoms, nor lyings, nor murders, nor any manner of lasciviousness; and surely there could not be a happier people among all the people who had been created by the hand of God." 4 Ne.3,11-13,5,15-16
We can have happiness in our homes and families as we strive to live the principles that Christ taught. Lasting happiness does not come from beauty or wealth or fame. True happiness and peace result from living a Christ-like life. Though there will be moments of sadness during our mortal existence, as we seek to emulate our savior, we can feel his peace and assurance even in the most difficult of trials. The purpose of our existence is to become like God, and God wants us to be eternally happy like he is. The way to achieve true happiness is to follow the example that Christ has set for us.
"And moreover, I would desire that ye should consider on the blessed and happy state of those that keep the commandments of God. For behold, they are blessed in all things, both temporal and spiritual; and if they hold out faithful to the end they are received into heaven, that thereby they may dwell with God in a state of never-ending happiness." Mosiah 2:41