It's rude to try and ruin someone else's good time.
Jack is at a party and his friends are playing a game that he does not really enjoy.
Jack wants the party to be fun.
Jack participates in the game and sucks it up, suggesting a new game shortly.
Jack disrupts the game and demands everyone play something else.
Everyone ends up having a good time and enjoying the party.
Jack derails the party, and everyone thinks he is being rude.