Chaos, I'm surprised that hothead hasn't been spoken to yet. Somebody like that would get fired in my office.
On the subject of annoying co-workers, one of mine spotted an error in my work and pointed it out in an email. I didn't mind that at all because we have a culture of excellence and everybody is responsible for ensuring that the work is top notch. I discovered later, though, she she blind-copied my boss on the email. I'm considered a fairly high performer and a firm believer in owning my mistakes, so the whole back-channel thing was just strange. I did confront her about the blind-copying but she made it seem like I was angry about her spotting the error instead of her sneakiness. I still don't think she gets it.