"You're single aren't you?"

A woman walks into a supermarket and buys:

1 bar of soap
1 toothbrush
1 tube of toothpaste
1 loaf of bread
1 pint of milk
1 single serving of cereal
1 single serving frozen dinner
1 can of Soup For One
1 16oz can of Miller Lite

The guy at the checkout looks at her and says, "Single, are you?"

The woman smiles sweetly and replies, "How did you guess?"

He replies, "Because you're ugly."