One of my books warned about people like that on the LSAT. Just ignore them. How much you brag is no indication of how smart you are, and how smart you are is no indication of how well you'll do - and how well you do arguably isn't even an indication of how you'll do in law school. LOL
Ultimately most of those people are just trying to psych others out (ie, the worse you do, the better I do) and from what I hear, it's REALLY common before law school finals as well.
The bottom line is that most people like that are just being jerks, and it's a waste of time to listen to them. They want you to focus on them, and not the test. Or, they just need constant gratification. Certainly, they're annoying, but take comfort in the fact that there's a lot of people scoring better than them, with more scholarship money, with better offers, that never brag like that.