This is one area where people are so subjective. I feel that being greeted, arriving at my destination on a timely, safe manner and in a clean vehicle is tops, 5*. Loud music, dirty, smelly car, will get you 4*. Gets lost, drives like a maniac , I'm delayed will be 3*. Racist, sexist foul mouthed will be 1*. I do not really have a set rules for 2* per se, however, if driver does add some extra stuff, such as interesting conversation, gives me some tips on places to go etc, will get a 5* as well. I don't downgrade if we have opposing views, however, I certainly do not talk with random people about hot topics, religion, politics, and the like in order to minimize confrontation, I'm the type person to be more agreeable to your beliefs, even if I really do not agree with them. On the flip side, I'm also a driver as well, and I've been on both sides of the coin. Someone who doesn't greet met, is ready on time, have me go to the store to pick up something, etc. will be downgraded.