"Daughter" joke

Late one Saturday evening, a woman was awakened by the ringing of her phone.

In a sleepy grumpy voice she said hello. The party on the other end of the line paused for a moment before rushing breathlessly into a lengthy speech.

"Mom, this is Susan and I'm sorry I woke you up, but I had to call because I'm going to be a little late getting home. See, Dad's car has a flat but it's not my fault. Honest! I don't know what happened. The tire just went flat while we were inside the theatre. Please don't be mad, okay?"

Since she doesn't have any daughters, the woman knew the person had mis-dialed. "I'm sorry dear," she replied, "but you've reached the wrong number. I don't have a daughter named Susan."

A pause.

"Gosh, Mom, "came the young woman's voice, "I didn't think you'd be this mad."