Tipping is great because it provides the customer with some leverage to pay a price they feel is fair. Not to mention it allows many many many many people to live somewhat comfortably despite working in what would be considered a lowly occupation. We haven't even talked about how service workers are salesman and saleswomen who are provided the opportunity to be compensated more for greater achievement, and the business in turn as well.

It sounds like the people who dislike tipping are the same people who struggle to stand up for themselves to salespeople, and feel pressured to pay extra just to remove themselves from the social setting. I don't mean to be accusatory, but I believe it's likely this is a major motivating factor to dislike tipping despite the complete advantage it gives to you as a consumer.