What makes me fall in love with things

I was inviting people to ask me questions on Tumblr last night, and one of the things I ended up talking about is what makes me fall for things (books, movies, TV shows) in a fandom kind of way. I decided to post that here as well, because it took me a long time to figure it out but I did eventually figure it out, and I thought it was interesting. There are always a few outliers that don't quite fit this, or fit it in unusual ways, but for the most part, this is what makes the difference for me between something I merely like, and something I write fanfic for and can't stop talking about to anyone who'll hold still long enough.

( Cut to keep from clogging your reading page )