Most Helpful Guy
Nope. I tip based on quality of service.
Most Helpful Girl
As a person who did waitressing to support myself, and a person who is an average looking (meaning i am comfortable with myself. i am fit 5'3, 110 lbs, just an average brunette, i smile a lot vs.) can testify that i was doing much better job that i was getting a tip averaging around 19% at the end of the night (which is good given that the customary tip should be around 15%) vs. a ditzy girl who was basically horrible (according to almost every other wait-staff at the restaurant) she was always getting an average of 30-35% even though she took the wrong order like instead of platter she bring a regular with no sauce, no fries, or she was definitely treating customers based on their races etc. i and three other wait-staff always believed that it was because she was a very attractive 9-10/10 girl with 5'9 height, blue eyes, long blonde hair and very skinny.
Maybe our claims were wrong but i do believe people tip based on attractiveness no matter how the service is.
i personally tip based on friendliness, being capable of making a small talk, knowing when to stop by and ask whether we need anything rather than every other second while i am eating (cuz i hate that) ...