They will never understand us

A wife asks her husband, "Could you please go shopping for me and buy one carton of milk and, if they have avocados, get six."
A short time later, the husband returns with six cartons of milk.
"Why did you buy six cartons of milk?" the wife asks.
He replies,
A short time later, the husband returns with six cartons of milk.
"Why did you buy six cartons of milk?" the wife asks.
He replies,
Spoiler: