A man sees in the world what he carries in his heart.

Perception is less neutral than it feels. A suspicious person finds evidence of bad motives everywhere, a generous one keeps meeting kindness, and each is convinced they are simply observing what is there. Both are partly right, because the world contains plenty of each, and what you carry decides which you notice. That makes your view of other people a useful, if uncomfortable, report on your own inner weather.

Next time you conclude that people in general are a certain way, pause on it. Ask whether that conclusion says as much about your current state as about them, and look deliberately for one example that contradicts it.