Someone mentioned expiration dates...that bothers me too.

Also, the loyalty cards don't bother me too much, as long as it's easy for them to solve it when you don't have yours/don't have one. I was at some store in San Diego, didn't have the card, and it took 5 mins for the guy to scan the store card...
Giant Eagle doesn't give you the sale unless you have a card; if you don't have yours, they check your ID to look it up.

Kroger and CVS just ask for your phone number...