This is a very intuitively appealing assertion, because (almost) everyone resents being told what is in their best interest if it contradicts what they think is in their best interest, regardless of whether or not the other person is right.  To whit, I have told a number of friends (as tactfully as I could) that they were in bad relationships, because they were, and I was worried about them.  Within a couple months time, all of those relationships had ended, because they were really, really bad.  But the number of friends who didn't resent me for telling them that is 0.<p>I think, in general, people are pretty awful at figuring out what is in their own best interest.  That's why the obesity rate is so high, credit card debt is so crushing, lotteries exist, and casinos are so damn profitable.  Now, that doesn't necessarily mean that politicians are better at figuring it out.  But I have no idea how you are supposed to successfully navigate life without the insight that you frequently make a lot of mistakes about what is best for yourself.