In the US, some states have lower minimum wages for restaurant staff because tipping is so expected and culturally ingrained that it's expected they'll make their money from it. So for people for whom tipping is not expected or expected only in classy places/where the service was exceptional, the US style is a little weird, but for people who expect to tip pretty much anywhere classier than BUrger King not tipping is a little weird.

For my part I tip pretty much anywhere that's Pizza Hut and up, but if the service is bad I might not.