So I've Been Told

Some would say that piety is the key to happiness.
But was is the point of being righteous in an evil world?
What good is generated from deeds which produce little or no results?
If the problems go largely unsolved (and conditions remain unchanged) - who benefits from good deeds?
If the doer of these deeds grows weary and becomes jaded - does the doing of these deeds even benefit anyone?

Does abstaining from;
Wrath
Greed
Sloth
Pride
Lust
Envy or
Gluttony
bring happiness?

Proverbs 14:4 - "Where no oxen are, the crib is clean; but much increase is by the strength of the ox."
It seems that even the wise men of the Bible recognized that there is little benefit to being perfectly clean.
If the goal is to remain clean - what work gets done?

Not money, not piety - what is the key to happiness?