Must be single

A woman was shopping at her local supermarket where she selected 2
litres of
low fat milk, a carton of eggs, 2 litres of orange juice, a head of
lettuce,
half a dozen tomatoes, a 500g jar of coffee and a 250g pack 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, "Cos you're ugly."