(Though sometimes guilty of it myself) I hate it when people (online) make cryptic remarks about how someone else online is being annoying. If I have any contact whatsoever with the person, I can't help but wonder (illogical and self-centered as it may be) if I'm the horrible person they can't stand. *sigh* I mean, I know that chances are it has nothing to do with me (how many people can I annoy in one day, right?), but you can't help but wonder...
...And this in itself may be construed as a mysterious "I don't like so-and-so"-type comment. Oh well.