There is nothing wrong with seeking happiness. God created us with human emotions, and expected us to experience them fully. But happiness, while fun in the moment, does not satisfy us for the long term. Flowing endorphins making us feel good temporarily is a poor substitute for the feeling of joy that is being described in Galations 5:22-23. The Holy Spirit does not bring us the momentary pleasure of a temporal world, but rather the deeper inner condition of joyfulness and thanksgiving found in communion with God. Happiness is a tenuous emotion, unsustainable. Joy is an enduring state of being, eternal.
Many people resolve to give up something that makes them happy for Lent, as a reminder of the sacrifice that Jesus gave up everything for us on the cross. But, just like happiness, that is a temporary thing, short term and short lived. No matter how much we give up on earth, we cannot save ourselves, not can we match the sacrifice of Jesus on the cross. God knows our limitations, and he has already provided the sacrifice.
Instead, he has asked us to seek joy in communion with him through the Holy Spirit. In Romans 14:7, Paul writes,
For the kingdom of God is not food and drink but righteousness and peace and joy in the Holy Spirit. (NRSV)
Happiness will elude us at times, but we can always find joy in the assurance of our salvation and the sure promise of spending eternity with God in heaven.
On this Ash Wednesday, I encourage you to move towards the joy in your life. Abandon the selfish whims that bring momentary pleasure and seek the permanent joy of paradise with the God who created you in his image.