In "Notes from the Underground," Dostoevsky (or his narrator at least) suggests that we can choose happiness (defined as maximizing our self-interest) or freedom as our goal, but not both. This is why utopias never pan out.

My own example: Always choosing the healthiest items at a cafeteria (assuming that we know or think we know) which items are healthiest) means that we are controlled by a sort of mathematical formula. Being able to select that huge slice of caramel cake (even though you know it's going to make you feel sick after eating it) means that you have some control over your choices. Making yourself unable to opt for self-destruction means that you have eliminated your freedom. In his prescription for healthy eating via the Zone Diet, Barry Sears recommends every so often going off the diet that provides your body with a balance and pigging out on an excess of refined carbs so that you remind your body of how a balance is important to your sense of well-being. I.e. balance becomes a choice and not a strait jacket..