Tipping practices vary greatly around the world.
In many Asian countries, it's not the norm at all. In some, it's considered an insult; in others, it's actually illegal. In Europe, it's generally discretionary and often not expected (although employers in the hospitality trade will tell you otherwise as an excuse to pay lower wages). Tipping usually occurs only in more upscale eating establishments or for services like taxis.
In our experience, it's only in the U.S. that tipping is expected in so many situations. And this is especially true of Las Vegas, which might have been built by gambling, but is fueled by gratuities.