i got an overdraft once, but once i figured it out it was their mistake.
i wrote a check for 50$ they said bounced and then at the same time i was charged for an overdraft, but when i checked my balance after i got a letter about it with the 50$ plus the fees around 20$ my account was negative what the fees where.
needless to say 2 banks caught hell for that one and i also nailed them for the late fee on the bill that the original check was wrote for.