Rabbi Michael Merdinger, "Is What We See Really What’s Out There?" (link):
Along these lines, we can explain a famous insight of the Ba’al Shem Tov once said that if you see someone with a particular flaw, you should examine yourself more closely, because you probably suffer from that very same flaw. Why should this be that I am likely to have the very same flaw that I see in another person?So true. Greedy people see everyone's actions as a function of greed. Conspiratorial people think that everyone does things out of a complicated conspiracy. Perverted people think everyone else is a pervert. Simple people take things at face value. Honest people assume others are honest. Etc. etc.
Because I see the world through my own personality, and I recognize my own character when I see it. If I am selfish, and I see someone else who is generous and altruistic, I will naturally suspect he has an ulterior motive—because that’s just the way I see the world.