Ask most of us what would make us happy, and chances are we'll name a change in our circumstances: We'll be happy when we win the lottery, get a better job, or see a smaller number when we step on the scale. "In our society, we tend to believe that happiness is something that comes from the outside, that happens to us," says William Fleeson, Ph.D., a psychology professor who studies happiness at Wake Forest University in Winston-Salem, N.C. In reality, happiness comes from within and depends on how you think about your life. Sure, external events and material objects like a new car or a bigger paycheck can give you a rush. But those feelings don't last. You can tweak your outlook so that you feel self-confident and serene whether or not you get that raise, win the lottery, or lose that weight.