Why is God so happy? It is because He has learned how to be happy, and he lives what he knows. What does He do with His time? He says he spends it "bring[ing] to pass the immortality and eternal life of man." He is always serving His children. He is always nurturing, looking after, teaching, and performing miracles for His children. He is the very embodiment of love.
If I want to be happy like God, I need to become like God is--think what He thinks, work like He works, do what He does. What work in this life most closely emulates the work of God? Motherhood. Motherhood is nurturing, caring for, teaching, and serving. Motherhood is helping children come step by step closer to the greatest good they can be.
Motherhood is love. Motherhood is happiness.
Some women teach that the greatest satisfaction for women comes from rejecting motherhood for alternatives. Others teach that killing unborn children is better than being an untimely mother. These women do not know God. They may know of Him and be acquainted with His teachings, but they do not know Him.
Of all the possible titles that can be obtained in this life, the most honorable and joyful title a woman can receive is the heavenly calling of "mom." No other position or accomplishment will bring more joy, more personal progression, more character, or more satisfaction. Motherhood is emulating God.