You must be single?

A young woman shopping at the grocery store goes to the express lane with
the following items:

1 pint of milk
1 short loaf of bread
1 small jar of peanut butter
1 grapefruit
1 pack of single-serving canned tuna
1 box of instant soup mix
1 small jar of spaghetti sauce
1 frozen dinner

The young man at the register scans each of the items and says to the young lady, "Well, I guess you're single, aren't you?"

With a blush and a smile, she rolls her eyes wistfully and says, "Gee, how
could you tell?"

"Because you're ugly."
I know it is a old joke but I received in a e-mail today and it made me laugh.

Peace