Understanding the Male Psyche

This is a story which is perfectly logical to all males: 

A wife asks her husband: “Could you please go shopping for me and buy one carton of milk, 
and if they have avocados, get 6?" 

A short time later the husband comes back with 6 cartons of milk. 

The wife asks him, "Why did you buy 6 cartons of milk?" 

He replied, "They had avocados.