The mistake most of us make is thinking we would be happier or finally happy when we get something or achieve a certain thing. That's our first mistake, thinking happiness is relative. That's pleasure.
Happiness should be absolute. The key to being happy is accepting life exactly as it is in that exact moment with all its craziness, perks and disappointment.
You're not going to be happy when you get more money because it will never be enough. You're not going to be happy if you lose weight because there will be the struggle to maintain the weight or a new goal to achieve. If you treat happiness as a relative concept (I can't believe I just said concept, blame my dissertation), once that thing passes so will your happiness.
Happiness is a state of mind, choosing to be happy no matter the weather or your situation. That's true happiness. I really don't know why I'm blabbing about happiness at 1am in the morning, LOL. Back to my dissertation....