It's rude to insult someone for being poor.
Rob, is who was playing a game with his friend, is arguing with his friend after they lose the game and his friend is insulting him.
Rob wants to say something back in retaliation.
Rob points out his friends gaming skills suggesting that he plays like a new player.
Rob brings up the fact that his friend works a low paying job.
Rob's friend laughs at the insult, and they keep playing together.
Rob's friend thinks that he crossed the line and stops playing the game with him.