I've had my bank charge over $300 in fees just because I overdrew my account by $20. They charged by transaction, and they ordered finalized transactions on my statement which would appear on the same day, by their monetary amount. Instead of by when they first were charged to my account. So a simply re-ordering of transactions would have resulted in a single $35 fee, not $315.
I asked them why they do this, and they said "Well, we don't want your biggest purchase to get declined because of insufficient funds, so we put that first. What if it was your mortgage?" But they don't decline any purchases. They approve any purchase made, knowing full well that they get to charge $35 for each one, regardless of the purchase size.
The only state they don't do this in, is Nevada. Because Nevada state legislature actually has laws against that shit.
So fuck you, Bank of Murricah. You go die now.