I personally never had a negative enough of an experience to warrant a bad rating, but I know people in the US that rated their drivers a low score for some reason (poor navigation, speeding, cell phone use), and they subsequently had an Uber rep reach out to them to discuss. It seems that they take the ratings very seriously. And it also shows because many of the drivers I spoke to were concerned about their ratings and even offer such amenities like water and cell chargers to make the ride more pleasant. As for yellow cabs in NY, many times I've witnessed the cab driver speaking on his phone and refusing to open the door before final destination is disclosed. Also, reports about not picking up minorities or people in less wealthy neighborhoods. These bad behaviors have gotten better over the years, but I attribute that to more competition from Uber