What is your tipping preference?

If you live in the United States how do you normally tip? What do you believe to be a proper tip? 15%, 20%, 25% or perhaps more or less.

Around the world I know tipping varies, many places do not require any sort of tip. The United States service industry runs on gratuities.

For those of you with good tipping habits, why do you tip the way you do?

I tip because I have been in the restaurant industry for five years. People treat you like shit and the restaurants breed alcoholic employees. The stress is often unseen or unknown to the average consumer.

If you tip badly, do you recognize that you are below industry standards and potentially damaging peoples lives?

I would love to hear other peoples opinions on the topic, let me know!