Got a few thoughts on this...
As a former server at a glorious corporate establishment, I can assure you that restaurants are not required to pay servers any more than $2.33/hr.
There is no raise system.
I also had to tip out the bartender and the host, based on my sales, not my tips.
So right away, if you tip 15%, that's not what I get.
I get 12%.
I tend to tip.
At that restaurant, it didn't make sense because the bartender would cash out the customer, yet rarely put the order together.
At a primarily carryout venue, I do tip when I grab my order.
Not based on conversation always, cause I know that most people show up to work to pay bills. Not be my new best friend.
I tip because I plan to spend this amount of money for my meal.
And typically, my meal is less than I expected to spend.
People tend to think of the service industry as low-skill.
I think we've all gotten completely horrible service.
And over-the-top phony service.
Service is a skill, and I don't mind tipping a buck or two or five for carryout, especially when I see that middle-ground establishment where I genuinely feel comfortable and the food is tasty.