Steve Levitt, the 'Freakonomics' guy, wrote a great paper where he took some people and looked at their major decisions. For some of the people, a coin was flipped, and if the coin said they had to make a big change, they made the big change. The people who made the big changes were happier than those who didn't. Of course, it depends on the person and context, but in general, read that Steve Levitt paper, think about the coin flipping, and, more often, make the big change. It's a risk, but it seems that, on average, it pays off.