I think then what you are talking about it societal norms. Here, it is common to smile when dealing with someone. I know in Europe that is not the case. So I think that you equate smiling with some kind of forced niceness. Customer service is a bit over the top here, not because of the tips, but because that is what society expects. Japan has an amazing customer service culture that, to me, feels very much above and beyond. But that is how they do it there. I would never consider calling them out for it and telling them that they need to change to do it how I feel it should be done. When we travel, we try to be be good tourists and do what is the cultural norm there. If coming here and tipping offends you so much, then I suggest going somewhere else.