Three elderly ladies were discussing the travails of getting older.
One said, "Sometimes I catch myself with a jar of mayonnaise in my hand in front of the refrigerator and can’t remember whether I need to put it away, or start making a sandwich."
The second lady chimed in, "Yes, sometimes I find myself on the landing of the stairs and can’t remember whether I was on my way up or on my way down."
"Well, I’m glad I don’t have that problem; knock on wood," said the third as she rapped her knuckles on the table. "…Oh, that must be the door, I’ll get it!"