When I look back at all the time I've spent playing games over the last 30 years I think probably the most significant moment was when I finally realised that failure didn't automatically mean I couldn't have fun.
I was 17 at the time and going through a “Power Gaming” phase. Winning was everything to me, I'd spend hours fine tuning my tactics, looking for ways to win. It didn't matter to me if something wasn't in the spirit of the game the only thing that mattered was victory. If things went wrong I sulked and blamed the dice. As you may have guessed by now another way of saying power gamer is 'a bit of a asshole', or 'not much fun to play with or against'. I think there must be something about the way that the minds of young male gamers develop that seems to lead a lot of teenagers down this particular rabbit hole. Its a cliché but you only have to look around in pretty much any online multi-player game and you will people not unlike my younger self, to whom the only thing that counts is being number one.
Thankful my salvation was on it's way in the form of a game of Warhammer Quest, a over zealous Dungeon Master (DM), and a cowardly vampire.