I went to leave a comment on a post just now and had the message "5 more to go". It took me a little while to understand what it was referring to but realised it meant characters after a few minutes. Perhaps this could be made clearer? Maybe something like "Your comment is too short. * more to go"
Edit: I've just noticed that before you start typing it says 'add at least 15 chars", I didn't see that when I'd started typing. Not sure if this is enough or if it need to be clearer. Could just be a case of PEBKAC!