Conversely I find it really annoying when I tell someone what I do and they say "That sounds hard" or "You must be really smart". It's dismissive. Like, that person has written me off as someone they're capable of interacting with. I get that it's intended to be complimentary, but it's quite alienating.

It's not like it's rocket science (apologies to rocket scientists), you could almost certainly understand if you took a few minutes to try. Not only that, but who says that's the only thing I want to talk about anyway?