I disagree.
I tip based on performance. I leave large tips, and very VERY rarely leave a shit tip. I've done it once or twice in my life.
If you are refilling my drink, and being nice, you are getting a nice tip (a.k.a. 20% for "I think you are just having a bad day, or 50-100% if you are freaking awesome and nice).
But seriously, the last time I can remember where I left a penny, literally, was at a hooters.
It was me, my fiance, and his coworker. I honestly don't remember what state we were in at the time, but they had just gotten off work and we were starving.
Our waitress came by, and completely ignored me. As in- asked the boys for their drink orders and took of without getting mine. K....strike one. It wasn't like she didn't see me, I'm sitting on the outside of the booth.
After she came back, I told her what I wanted to drink and she rolled her eyes, taking our app order and regular order ( of which I had to let my fiance know what I wanted because she legit would not even look my way to take my order). She disappeared for 30 minutes. I still didn't have a drink, the boys drinks were empty. She shows up with the food, and still no drink and no refills.
I'm pissed at this point and notice another nice waitress walking by, and say "excuse me, miss, I know we aren't your table so I understand if you cant, but can you please get us a refill, and me a drink? Our waitress has disappeared".
Well, that sweet young lady went and got us refills, and me a drink, and I handed her $5 just in case it took her away from her table, and as such took away from their tip.
We ate, food was good, and we never saw our waitress again, even after trying to get a manager (who was apparently in a meeting). We ended up getting that same nice girl to grab our check for us, and we handed HER actual tip money for being so kind (~ $20, so $25 total on a $30 meal) and we each left a penny on the table for our original waitress, who we watched walk by our table as we were headed out the door (from a man's lap across the restuarant)
So no, not everyone deserves a 20% tip. But we make sure to go above and beyond for those that do. We know that sometimes people just have a bad day or they are new.
But for me, as long as you aren't an asshole or a bitch, you are getting atleast 20%. Shit, we have even tipped at fast food (slyly, so they don't get in trouble) if they go above and beyond, or it is xmas time.