Read the blog post above. As a former server, tipping poorly/not at all is a deal breaker for me.
In the US, tipping is part of the cost of eating out, among other activities. It really shouldn’t be optional, and it should be calculated into the budget when you’re traveling or going out. It’s like having to pay sales tax. If the service is awful, say something and then tip accordingly, but service is still a luxury, and you need to pay for it. That’s why in some countries, there’s a 10% service charge added. It really would be easier if it was just automatically added to the bill, but here you have a choice, where the culture doesn’t dictate that service should be beyond satisfactory and tipping is not required. (Re: Tipping in Taiwan)
P.S. If you’re not so good at the math-stuffs, in Nashville, just double the tax. That’s at least 15%.