Judgmental people are most likely insecure themselves, and plaster their own faults on someone else. Ignore them, because you are better than them. Of course, none of us can escape from judging a bit ourselves, but if people are giving you dirty looks or talking behind your back, then these people are asking for your attention and worry. And then they feed from that. Don't let them get to you. They're just people who are looking for their own security (and they're not doing it right).