What does it feel like when loving your friend as a friend and having a crush on them on top of that turns into actual no-fooling being in love with them? Can this happen in absence of doing anything actually romantic with them? Actually in general how the fuck does this falling in love shit work? Fiction cannot possibly be a good guide to this.
It can absolutely happen in absence of doing anything romantic with them. As for more actual answers, I will rack my brain, because I have been in the same situation but alas, my long-term memory is absolute shit. Paging @a tiny mushroom who might remember better than I do?
Hopefully not a total necro but anyway: "In love" - the feeling is reciprocal. "Crush" - intense sexual interest and/or romantic infatuation; the desire to have a relationship with someone (There's a friendship version too, but friendships are almost always possible to start forming right away) "Romantic" - a word used by people who have never seen a functional nonfictional relationship. Stable relationships tend to be kinda low on the 'romance' quotient, because the pair have other things holding their relationship together. Basically, the boundary between "being in love" and "a crush on a friend" is whether the feeling is both mutual and expressed. (...Or at least that's what the general opinion is in the countryside around Washington D.C.)
People also tend to conflate having a crush with being in love, but I think I'd agree with Ben that 'love' is generally what happens when you've already been in a relationship with them for a little while. IMO it's something to do with knowing them a lot better, and knowing them in the context of a romantic relationship, that makes it love.