It really depends on the flaw. People's psyches can lead them to do all sorts of ridiculous things. I may think I have some kind of a flaw that nobody else sees, or would even consider to be a flaw.

For example, I'm not the best defensive catcher in baseball. Sometimes my throws to second base are absolutely terrible. However, I try to make up for that by being as aggressive as possible on the bases. If I can stretch a single into a double, or a double into a triple, I will. I KNOW I do this because if I make an error in the previous inning, I feel like it's a huge glaring mistake, and I don't want people to really think about the errors when they think of me playing. I'd rather have them see me as the guy who always busts ass, takes guys out sliding, and gets that extra base.

I feel like I couldn't really point out other situations in other people from a personality standpoint, because even if we say we know someone, we never know them as well as they do.

I think it's a good thing to know your own flaws and to know what makes yourself tick. How you go about addressing them is really the business of each individual. Some people will admit they have a flaw, other people try to draw attention away from their flaws with other things, and other just don't care.