Tipping incentivizes a waiter to over-promise (sure I can take care of both of these sections!) and sometimes results in under-delivering.

They intend, and try to give good service 99% of the time I think. So for me at least, that's why I have trouble not tipping. It's the thought/effort that counts I guess. I almost never have a less-than-great service situation and attribute it to the waiter just being lazy. Can't remember the last time that happened to be honest.