At a party, a young wife admonished her husband

At a party, a young wife admonished her husband, “That’s the fourth time you’ve gone back for ice cream and cake. Doesn’t it embarrass you?”
“Why should it?” answered her spouse. “I keep telling them it’s for you.”

This joke is funny because the husband rudely lied to everyone and told them that his wife was eating a lot of ice cream and cake when he was actually the one that was eating so much ice cream and cake.

When people are rude to each other it is often considered funny, and also when people lie it is also considered funny too.