I once held a temp position in QA. I found a nasty, but obscure error that wouldn't have popped up until way down the line (and also wrote and submitted a fix). The original developer was annoyed, but the team lead was pretty happy to see me do exactly what I was brought on for: Abusing the app in all the ways I could imagine a user not on the actual dev team doing.

So yeah, great job tester, great job developer, now we wait for the user to try actually sleeping in it and finding it terribly uncomfortable in the long run, or exerting lateral force instead of the vertical one it was designed for.