After an elderly couple starts getting forgetful, they visit their doctor. Their doctor tells them that many people find it useful to write themselves little notes.

When they get home, the wife says, "Dear, will you please go to the kitchen and get me a dish of ice cream? And maybe write that down so you won't forget?"
"Nonsense," says the husband. "I can remember a dish of ice cream."
"Well, I'd also like some strawberries and whipped cream on it," the wife replies.
"My memory's not all that bad," says the husband. "No problem -- a dish of ice cream with strawberries and whipped cream. I don't need to write it down."

He goes into the kitchen, and his wife hears pots and pans banging.
The husband finally emerges from the kitchen and presents his wife with a plate of bacon and eggs.
She looks at the plate and asks, "Hey, where's the toast I asked for?"