Well, wait, you aren't required to tip above. You're right in that etiquette requires tipping a 'normal' amount (15%) but there's always the potential that you tip above and beyond. Servers are compelled to prove to you that above and beyond tip. Hey, I agree with you there. At sushi places, the sushi chefs have their own tipping jars I always make sure to frequent. Eh, I'd rather work at a place where I get tipped because I know I can make bomb tips because I can work it. I don't want to share my tips, I don't want to make the same amount no matter how good I am to my customers. I will dominate them with my service skills.And if you don't tip, or tip lowly you get dirty looks from people that came with you. So essentially you are forced to tip a "regular" amount, or even above. Which completely eliminates the feedback/rating part.
I don't see why it should be limited to restaurant servers, when they aren't the only people serving you.
All it does is drive up costs for the customers and makes the worker stressed out about being paid a "normal" amount.
As I said, I'd rather see tipping as just a cultural thing where you'd tip whenever and wherever good service was found. Not just for waiters. I see no problem with genuinely giving extra for hard/good work. But when it becomes culturally required, that's when I have a problem. I shouldn't have to tip, just because you don't get paid enough. I should tip when I feel like you did a good job. I see it as a "donate" button on a website. You don't have to click it. But you do if you like the website.
Hey, that's reasonable. Maybe I'm sympathetic because I work coffee where it isn't culturally required. But pro tip: tip your barista at least if he makes you a specialty drink. Or assume he doesn't like you. ;) (If he just pours you drip coffee, another story. But if he's a nice dude and makes you a bomb ass latte, all it takes is fifty cents and he makes his 15%.)