The Happiness Factor
From Head to Heart: The Science of Emotions

You can't buy, inject, drink or swallow tablets that will give you happiness. Winning the Lottery will give you fleeting happiness but then what? Suppose you get a devastating illness the next day - where did that Lottery happiness go to? You are in charge of your happiness and it is you who has to decide that you are going to be happy regardless of circumstances or situations. If you allow outside influences to dictate your thoughts and feelings you lose self ability then you are almost finished...