yeah i've had those..
An embarassing one was when a customer asked for an extension of pymt, i told him over the phone that i'll try my best to get him the extension he needed.
He sent a formal request through email, but after i checked his file i thought otherwise. So i forwarded his email to my manager, with an added comment on top to help her make sound decision (my comment basically
said ; This customer's crap! never pays on time, he's approaching his credit limit, he hasn't been meeting the budget we set.. yada yada yada..) .. and guess what.. instead of pressing 'forward' i pressed 'reply'
of course ...it was sent to him.