> display no enthusiasm when communicating about things that I care about because I expect that the other person won't be interested or care

This resonates a lot, and especially in "our community" of tech enthusiasts. I don't display enthusiasm about electronics, pcb design and assembly, with non nerdy people because I don't expect any form of interest (which is compounded by the assumption the person won't understand a word about it).

It got especially reinforced of late as I made a foray in woodworking to build myself a bookshelf from scratch with a custom design. There is something about non-tech hobbies that anyone can relate to (everyone was stoked by said bookshelf) that makes it easier to share. Even the layperson can grasp the design challenges faced in such hobbies, including nerdy but non tech ones (warhammer figurine painting is the first that comes to mind). OTOH when I show a custom-made PCB to someone, I just get a "ok cool".

> I wouldn't be surprised if I subconsciously have chosen friends who re-inforce those beliefs as well

There is also a strong tendency to vary friend groups and "get out of your bubble" if you think you're boring, to get "non-boring" people around you. Which can be healthy but highly frustrating, because you don't get to share stuff with them.

I can't wait to get children to share those interests with them.