Tipping is really supposed to be for a ‘service charge’, and I don’t see that as a bad thing given the subsequent quality of the service industry in the US. But I don’t really agree with it bleeding into other areas.
Eg, you tip a taxi driver, why, because he managed to drive you somewhere without hitting anyone? Fair enough if he went above and beyond, helping with bags or whatever. But if it’s ‘expected’ otherwise they’re being short-changed, then really what they need to do there is raise their fares to be more representative.
But then there’d be nothing you could do if the cab was dirty, he didn’t know the way, he played music you didn’t like, had a loud conversation on his cell phone, didn’t give cyclists enough room when overtaking etc. If there’s no tipping you’d have to pay the full fare regardless. With the current US system though you can choose not to tip. Having an optional part of the price for so many services is great from a customer point of view