How does a man become happy? By obtaining that which he desires.
But how to explain those poor souls who, having everything, remain unhappy? If a man desires that which is evil, and obtains it, he will not be happy.
A happy man is one who desires that which is good.
If we are seeking happiness, then, we must understand that it is merely a by-product of seeking after goodness.
Seek after goodness, and happiness will result.