I hate the composition box options.
The text is either way too big or way too small for anyone to read and none of the fonts change size at ratios that make sense when you're trying to blend several fonts into one post. I generally try to leave things big enough to be readable - but there's not subtlety to this thing at all. Perhaps I'm doing it all wrong, perhaps I just don't know my way around html, etc enough yet. It all just feels so limiting.