There was a hidden input with the calculated price from the client. It was passed to the backend. It was not validated on the backend. The customer was charged that amount. It would have taken a long time to fix...

Lesson 1 of developing a project with managers: never make it known that solutions to some bugs are simple. Managers will assume that all bugs are simple and require little thought and effort. Then, when there is a bug for which you have no idea what the solution is just by looking at the issue, they will become upset.

Seen in Vegas

Friend bought me cards for my birthday. There's no way I'm learning brainfuck...