Most drawn out board game in history.
My brother wanted to enact a rule that you could take a property from another player if you paid more than them for it, and they could steal it back if they put up more, etc., kinda like an auction. Well it led to the game being dragged on longer due to all the bickering my brother and I had. I think one time, I spent $350 for Connecticut Avenue. I'm not kidding.