The worst I've seen is identity theft ocurring right before me. And it was an Administrator. Someday when I'm done with that saga, I'll post the full details. Suffice it to say, I highly recommend different passwords for everywhere you go. Annoying, yes, but always a good idea and there are tools (my current favorite
) to help you recall them all EASILY.
As has been noted, trolls feed from getting attention, so the objective, of course, is to ignore them. Sometimes
they go away, but more often than not the staff get tired of their antics and they get perma-banned. Ironically, the incident today that spawned the parent of this thread was followed up with a PM from a fellow veteran member of the board telling me the mods and Admins have been considering what to do with the kid's account. As pig's noted, you can almost always smell them a mile away.
As for spelling, grammar, capitalization, and the like, the only thing that bugs me is ALL CAPITAL LETTER USERS. That's the online equivalent of shouting, and is not just frowned upon but a bannable offense in many places. If you don't write easy to read notes, it can reflect on your intellect and often can be ignored because its too difficult to disseminate what the hell was just written. So while it does take time to type out something "properly", it advances people's opinion of you subconsciously.
PS: Don't mind pig, he's just a Spelling Nazi