[Zippy]

I usually do that....just say bye then log out or close window. Ill wait for a short while but as long as Ive said bye then I feel ok. Least they know you've gone. I usually have several windows open so can sometimes be distracted elsewhere and they think Ive gone without saying bye. Thats worse.

plus if you say you have to go and then stay there waiting ages for their reply you kinda look like a liar.