Fair enough.
Maybe I've been doing what I do too long but I just cant be arsed getting annoyed at customers anymore. I tend to just ignore them for a while and adopt the attiude of not really caring. When they're relying on us to fix their pc/server/network or whatever they soon come round.
e.g some person was being a complete twat on the phone. I could fix their problem in 5 mins. Nah, I think I'll let them stew for an hour or two.
There, I've just broken my rule on talking about work.