I tip for great and good service..... Bartender better know what i want to drink and know how to get me drunk by the 2nd drink... I'll be leaving a nice top..
I tip for good service and extra extra for GREAT service. So if you're mediocre, it will be reflected in the tip.
That being said, customers, including myself, don't have shit to do with how a server is paid by their employer. Too many waitresses walking around thinking they should be tipped big because they look good but don't properly serve. Doesn't work that way, bitches.