By "violence-related", I mean nothing trivial like a glitch/exploit or a simple reference to another game.
My favorite, for example, was when in C&C: Red Alert 3, there's a mission where you invade Santa Monica and you get to destroy the wretched EA LA Studio located nearby with whatever the hell you want. Tanks, infantry, robo-copters, chargable lazors, etc.
It's a good way to express some rage towards them, plus the infantry say something witty when you do so.