I have to agree Happy...I was raised on the 10% for normal decent service and 15% for exceptional..."tip creep" is likely due to servers trying to make people feel as if they are cheap if they don't pony up a certain amount and it works on a lot of people.

It happens when people 'expect' or act entitled as you mentioned...I live in Central Europe and tipping is not standard here...but since the foreign tourists who don't know any better do it the servers now expect it from everyone and act like jerks when you don't. And...they get paid a normal wage without it so it isn't like the guy making 3usd per hour and needing the tips to make ends meet.