A buddy of mine recently got blood poisoning from a cat bite on their hand, it's rare but it does happen.

Personally I don't worry when my car scratches me, but I still wash it and watch to make sure.

I had cat scratch disease last year, and do not recommend it. Very painful and uncomfortable. If a cat bites or scratches you hard enough to break skin, clean and disinfect immediately. If you feel ill after a couple of weeks to a month, test yourself and kitty for Bartonella Henselae. If positive, prepare for three months to a year of misery.