Sadly, so many people think happiness is something that you have to chase after; an object you have to acquire, a person you have to win over, or a place you have to visit. If you invest your happiness heavily in external things, you'll be chasing them until the day you die, like drinking salt water trying to cure thirst.
To be happy, you have to be harsh with yourself. You have to set aside your pride and discover your faults and weaknesses, as well as your strengths. And most importantly, you have to be blatantly honest with yourself in introspection. This all leads to the most essential ingredient of happiness: self-respect. If you don't have this, you'll never have happiness.