Humorous goof up

I have a funny story about making sure you read the coupon carefully before presenting it. It is definitely a "what not to do" example.  I went through the McDonald's drive through on the way home today to grab some free fries I had a coupon for. I ordered them, gave the cashier my coupon and started to drive to the pick up window. In my rear view mirror, I see her stick her head out the window and loudly say "Ma'am."  She proceeds to inform me that the coupon is for Wendy's.  Like I said....what not to do. 

Clearly that was a message I should not be eating greasy french fries. I told her to keep it and use it at Wendy's herself.  She thought that was great!