A kid and his grandparents were at their house. Grandpa saw that his grandchild was eating ice cream.
Grandpa: Honey!
Grandma: What, sweetheart?
Grandpa: Get me some ice cream. Don't forget, ice cream, ice cream, ice-cream! You have alzheimer's disease (can easily forget), so don't forget, ICE-CREAM!
Grandma: What are you talking about?? Your alzheimer's disease is even worse than mine! Okay, I'm going to get your ICE-CREAM!

Afterwards, Grandma came back.
Grandma: Here they are, the hotdogs you asked me to get.
Grandpa: Hahaha.... I told you so... you really have Alzheimer's disease.............you forgot the ketchup.