On several occasions I would overdraw my debit account, notice the issue and deposit money, and then continue to make purchases with the newly available funds. Despite having sufficient funds, at the end of each day, Fifth Third Bank would reorder the day's transactions to maximize the overdraft penalties, as if all of them had been settled while overdrawn. Their customer support team would pretend this was actually beneficial to customers and launch into a nonsensical explanation where one of the terms involved was, literally, "the matrix." So you'd be sitting on the phone in disbelief as they talked about "the matrix."
Anyway, there was eventually a class action lawsuit over it. Ever since then, my inclination is to regulate the hell out of these sleazy institutions. They clearly can't be trusted to act in good faith.