Apart of what I posted yesterday there is more to this whole happiness issue. I feel (just my opinion) that selfish people cannot be happy. A self-indulgent lifestyle is a one way ticket to unhappiness. We need to look away from ourselves and reach out more. Most of us have more than enough already. In 2 Corinthians 8:14 it says "...at this present time your abundance being a supply for their need,..." "He who gathered much did not have too much, and he who gathered little had no lack." (v.15)
Read Ezekiel 16:49-50 and you will see people of an ancient city who suffered God's judgment, because they led a self-indulgent lifestyle. We should desire to please God and serve others, not ourselves. "Do not merely look out for your own personal interests, but also for the interests of others." (Philippians 2:4) The more we serve Christ, the less we serve self. Thus the more happy we will all be.