Stopping the dam from bursting in the Superman game on GameCube is the only button mashing section of a game that actually halted my progress. It was my friend's game and for a couple years there were a bunch of us that would periodically try and fail to beat this level before I finally got it one day. That felt like my greatest gaming feat at the time and I don't remember any other part of the game being close to as difficult as that section. This was all when I was a kid, so for all I know it's not actually that bad and we all just sucked, but I remember it at least being hard enough to make my fingers hurt.