Actually, I once was. I got the game Halo for pc for christmas and after finishing the single player, I started to play online. I sucked badly because the other team was a clan and my team was just a bunch of players. There was this flamethrower in our spawn that I used to kill their team from stealing our flag but I also teamkilled once with it. Apparently they said to stop but before I realized that, I was banned from that server. Never played multiplayer again for that game.
Have you ever finished a long singleplayer game (gameplay of at least a few hours) without cheating once in it? And cheating is not just using cheatcodes, but also if its a puzzle based game, look up a solution, or otherwise ask for help on how to continue.