Just left a nice fat ZERO on Saturday night, myself.
Waitress was MIA too often, resorted to getting things myself (straws, napkins, lemon wedges). Then my order came wrong, to which she insisted that it was in fact what I ordered till she found the hand-written bill and realized she was wrong. So my gf ate while I waited for my correct order, which came to me rushed and without an apology.
I'm generous when the service is on point, but I can be brutal if I feel slighted.
BMW: 2011 AW/Black E92 M3 DCT - 2010 BSM/Tan E90 335i AT
Other: 2004 AW GDB STi 6spd - 1991 Nero/Nero 348tb 5spd