 There's one colleague that this guy mentions. We used to have a good rapport, always sharing jokes, but then suddenly his behavior toward him changed. He became curt, would barely smile, and the conversations became strictly work-related. You've had that happen probably in high school or college or something. Somebody get mad at you. You don't know. It's not necessarily to mean they don't dislike you necessarily, but if you notice this, while they remain the same with others, it could be a subtle sign that they can't stand you.