You're also in that camp for me DH, as you know. Agree, generally even within my friends circle and wider acquaintances, I noticed even though most of them are very different to one another, they are all similar when it comes to innate intelligence, curiosity and open mindedness. We're always picking something up from each other and of course that helps with personal development too rather than an echo chamber. I never intended to "pick" friends on this basis but it just happened, of course being fun to be around is cool but I guess it goes hand in hand with the other things I mentioned.