The happiness of the Lord's people defined and described by the Word of God. Lasting happiness that makes the passing things of this life pale into insignificance. (What is the recipe for happiness in marriage?)
The only way of true happiness in this life and forever is a relationship with God. Why would anyone rationally resist this love of God?
Ps.144.15Happy is that people, that is in such a case: yea, happy is that people, whose God is the LORD.