Proverbs 29:18 When people do not accept divine guidance, they run wild. But whoever obeys the law is joyful.
It is impossible to feel joy when we are worried, or when we are feeling guilty. When we feel angry we cant feel joy. When we are running from something or when we are drowning our sorrows (in anything... alcohol... drugs... TV.... football... golf). So often we are busy staying busy so we won't "feel" this mistakes or our past or the mistakes of our present. It is impossible to feel joy when we don't feel safe.
When we obey God's law we are free to feel great joy... we can even feel joy in the hardest time. Every time that happens to me I am totally amazed. First when we follow God's law we live under His protection so we feel safe. When we choose God we choose forgiveness which takes care of all past guilt's. When we follow God's law we forgive, forgiveness erases anger. When we follow God's law we live life in a way where we don't carry around sorrow. When we follow the laws of God we are free to live in joy!! Amazing joy!
We can go about searching for happiness/joy. Or we can simply trust in God and do what He ask of us. We could spend our life searching... or we can just love God and follow his law then joy will find us!!