Why you never question a drunk

A woman was shopping at her local supermarket where she selected:

A half-gallon of 2% milk,
A carton of eggs,
A quart of orange juice,
A head of romaine lettuce,
A 2 lb. can of coffee,
And a 1 lb. package of bacon.

As she was unloading her items on the conveyor belt to check out, a drunk
standing behind her watched as she placed the items in front of the
cashier.

While the cashier was ringing up her purchases, the drunk calmly stated,
"You must be single."

The woman was a bit startled by this proclamation, but she was intrigued by
the derelict's intuition, since she was indeed single. She looked at her
six items on the belt and saw nothing particularly unusual about her
selections that could have tipped off the drunk to her marital status.

Curiosity getting the better of her, she said "Well, you know what, you're
absolutely correct. But how on earth did you know that?"

The drunk replied, " 'Cause you're ugly."