the most friendship-ruining game in history: Mario Party. A lot of you probably guessed this, because at some point Mario Party became known ONLY for this. The game is pretty much the perfect storm for friendship-enders (aka "endships"):
Extremely long games, much of it based on chance (aka "The Monopoly Syndrome")? CHECK.
Forced co-op competitive play, leading to lots of yelling about your partner not rowing right? Double CHECK.
Lots of straight up individual competitive play, with idiots BUMPING INTO YOUR ON THEIR DAMN BUMPER BALLS AND NOW WE'RE BOTH GOING TO LOSE GODDAMMIT?!?!? CHECK.
Stealing Stars by paying a ghost? WHAT THE SHIT, GARRETT?!
The end RESULT is that you have no friends, your hands are mangled from some horrifying joystick spinning, button tapping, or Wiimote shaking, and you're playing Mario Party by yourself, which is the only thing sadder than playing Mario Party with friends.