Every conversation slightly changes what both people know afterward.

No exchange leaves either person exactly as they were. Even a small one shifts something, a fact, a nuance, an impression. Over enough conversations, the people you talk with regularly are quietly forming what you think, and you are doing the same to them, mostly without either side noticing.

That makes who you talk to a consequential choice rather than a social one. Look at your regular conversations and ask what direction they are moving you. Then add one that stretches you, and be a little more deliberate about the ones that only ever confirm what you already thought.