At A Restaurant, I Tip Two Through Five U.S. Dollars, No Matter What!!! Even If I'm In A Country In Which It Is Not Customary To Give And Or Receive A Tip!!!
It depends on the service and the establishment. I've been known to tip as much as 50% but my bill was only about $50. I tend to pay the price that feels good to me. I don't count percentages. I don't tip for horrible service... period.
However I tend to tip about 15% and above.
Typically I round the tax up and double it. If the server was really good, I tip more. If the service was poor, I still leave a tip and a note about what could have been better. You never know what people are going through in life. I also let a manager know when a server is top notch, often times only the negative is expressed. I always tip my nail and hair girls at minimum 20% and they work me in and comp things time to time. I like treating people well, but sometimes people don't deserve it and I just take my business elsewhere. I don't prefer when people make a scene or behave in a condescending manner, so no matter where I am. I treat others with respect.