You should tell someone if they offend you.
Greta, a Christian, is hanging out with Stacy when Stacy makes a joke about Christians.
Greta wants to respond to Stacy.
Greta tells Stacy that the joke is in bad taste.
Greta changes the subject but does not tell Stacy she doesn't like the joke.
Stacy will not make jokes about Christians anymore.
Stacy will continue to think it's okay to make jokes about Christians.