20 is the new 15

Attention people who eat in restaurants: This just in - 20% tip is the new 15%. NPR reports that the growing accepted "norm" in the business is if you have an excellent server- 23% is an appropriate tip. A good server- 20% tip. An "ok" server 15-20% and unless the server was insulting, mean etc., you should always tip SOMETHING!
NPR did mention "if 20% is the new 15%, where does the top tip stop?
I say, don't be boxed in by your usual way of tipping. If your server makes you meal run smooth- makes you happy or goes above and beyond; TIP them! And if your meal is only $15, but your service was the best part of your meal LET YOUR TIP REFLECT that! Wow someone, make their day! Especially if they've made yours!
But I'm Just a Waitress, What Do I Know?