Anyone who’s ever played one match of Overwatch quickly realized their best chance of winning was putting in effort throughout the entirety of the match. I think it’s highly likely, they never stopped playing the game for the rest of the match after they got one awesome play either, never actually believing that one moment was enough, and always knew the value of consistency. Im willing to bet they understood this even before playing OverWatch.
Perhaps the reason you don’t understand why player complaints (and neither will you ever at this rate) is because your first assumption is that they’re stupid.