Are you really telling a teenager that there’s something mentally wrong with people who choose to make a career out of working in restaurants? OP hasn’t been behaving weirdly, she’s been purposefully rude to her coworkers. It may be very difficult to break the pattern where she is, although she could start by apologizing to them for acting so immaturely. She may be better off aplogizing then finding a different job that she approaches in a more mature manner.