If it works so well, and I'm pretty damn convinced it works well for you, but if it works so well in general why is there a complaint? Why the thread?
All a European has to know is tip 10-15% in USA/CA, and all an American in EU has to know is don't tip unless you're really happy with the service. See the Wiki pages for details about specific regions (EU countries, US states). Wikitravel probly also contains this info.
...but we got people like e..8 or whatever his name is complain like a lil.. and openly saying he'd denial of service customers who don't voluntarily tip. See where I'm coming from? It seems the system doesn't work well if you got drivers like that, now does it? I almost wonder where e..8 work, in which area and for what brand. I'd evade them for sure. Same with the spitting kids, but yeah, anonymous behind your monitor w/o telling who you work for terrorizing those who don't tip, or don't tip enough...