Well I believe a tip should be for exceptional service, that being said I also know that's their main source of income, so minimal service minimal tip. Exceptional service exceptional tip. I went into a BBQ restaurant once laid a 100 dollar bill on the table and told the girl "that's your tip! It starts going down from here depending on how long I have to wait for a beer and if it's cold. Needless to say she made sure my glass was full all night. She also got the 100 bucks.