Heh, the stuff I've been screwed on the hardest is stuff where the boss or the HR officer has said "it's just (standard|a formality|the norm)", despite not encountering those things in other workplaces.

Edit: I guess the moral of the story is that something being dismissed as 'standard' is a red flag to confirm that on your own time. Maybe it is a standard, but if that's the only explanation they're using, it's not good enough to stand on it's own.