Some people have been ill-informed about credit cards by the news media, while others are too set in their ways to change.  A few just don't have the self-esteem to stand up for themselves.

Still others have a perfectly legitimate reason for not using a rewards card to claim their fair share:  they feel that credit cards may tempt them into excessive spending: If that's you, try out a rewards "charge card" instead. It must be paid off monthly, so naturally you'll use it only if you have enough money banked to cover the charges.