I thouroughly loathe the tip culture in the US. I was not born here, but lived here for many years. My standard is generally 15 to 20%. 15 when everything went smoothly, and 20 when given excellent service. Occasionally I will tip more for really outstanding service. I been told many times I am on the lower end of the tipping scale, that I should tip more.  To me, tip is a token of appreciation for service rendered. Yet it feels more like an obligation to tip regardless the quality of service in US. I am a heartless monster if I don't give enough money to support the livelihood of my waiter/waitress. I eat out a lot less nowadays. I tend to produce food with higher quality and more nutritious ingredients out of my own kitchen anyways.