I usually tip (if the service was good) around 25%, but yes I'm aware this is abit much. I'll go as low as ten if the service is pretty bad, and if they can't treat me with respect (rarely the case) I just won't tip. But yeah, I'm pretty lenient. Don't take too long throw a please and thank you in there and I'm happy. Bam 25%.
A good friend of mine waits, he's always very nice and very attentive. One day he got stiffed on an eighty dollar meal by a family. He followed them out to the car, said "excuse me, was their any problem with the service or the meal?" "nope." "Alright then, in the future if you don't want to tip there's a restaurant right across the street where it's not necessary." and points to a McDonalds. The dude complains to the owner of the restaurant, the owner's this old Greek guy "well why didn't you tip then if the service was good?". Boss totally stood behind him. Cool guy. I agree with the sentiment completely. If you're in the states and you don't feel like tipping your wait staff when the service is good, then please go to McDonalds.