Bad memory

An elderly couple are sitting on a park bench arguing about which one has the worst memory. After a while the old lady asks the old man to walk over to Dairy Queen and get her a hot fudge sundae with whipped cream and peanuts on top. She tells him to write it down because he will forget what he was going for by the time he gets there. He says " I won't forget . You want a hot fudge sundae with whipped cream and peanuts on top". He leaves and is gone for a long time. When he finally returns he hands her a bag with a cheeseburger and fries inside. She looks in the bag and says "I knew it ,I knew it. I told you to write it down". He says "Well ,I got a cheeseburger and fries just like you asked". She says "Yes, but you forgot the mustard and pickles"!!!