There are several "hard" things in CS/software-development that I keep having to convince myself I do, in fact, understand, every time they come up in a discussion like this, because I find them really simple and wonder whether maybe I missed something. One's pointers. I don't get what's so hard about them. I mean I get why they might be tough the first time you're introduced to them but it's exactly the same kind of reasoning/structure that's used all over the place in programming, so if one can't understand pointers I'm not sure how one's programming at all, really.