You didn't keep track of your expenses, and transactions do not process instantaneously. It's not the bank fault you don't keep track of how much you spend and had to ask them. When they told you "oh yah, you have 19 bucks left" you should have asked if that included the 16 bucks you had just spent. Gas stations often put "debit" through as "credit" so it doesn't hit your account until days and days later. Which is why YOU should keep track of your money, not the bank.

So in other words, it's not the bank's fault. It's yours.