A promise is a promise

After seeing on my cell phone that I had a missed call from my mom this morning, I called her back.

Me: Hi, you called?

Mom: Yes, did you get my message?

Me: Not yet. I didn't check the voice mail.

Mom: The lady said she'd deliver my message right away!

Me: What lady? You left a message at my office?

Mom: No, the lady on your cell phone. 

Me: A live lady?

Mom: No, the recording. She promised she'd deliver the message right away.

Me: Um, Mom, the lady on the recording promised you this?

Mom: Explicitly.

Me: And you believed her?

At which point we both started laughing.