I did the DUMBEST thing. I went to pay off my credit card balance, and accidentally made the electronic payment from the wrong account (picked the wrong one from the pull-down menu), so both the bank and the credit card company charged me NSF fees. I didn't notice for a week or so until the payment never cleared from the right account, and by that time, the credit card company had tried THREE times to process the payment, and the bank charged $35 for NSF every time. That one little clicking error was really expensive!