421. Didn't checkmate on the last move as he ran out of time.
422. tries to rickroll opponent so he could resign
423. Thinks that the Martin bot is Martin Stahl.
424. Plays BlahBlah's hit "Dummy, dummy, dummy" on his headphones during all of his chess games
434. Thinks his rook is a queen.
i do that and i checkmate my opponent
435. Thinks that the rook is an elephant.
436. Goes to the Restroom in the middle of the match and plays video games on his/her watch and forgets about the chess game and loses all games just like that.
437. relies on draws to not lose even though they gain no points
438 eating while playing and getting grease all over their mouse/trackpad/screen
421. Didn't checkmate on the last move as he ran out of time.