Tipping in the service industry

[Aoi Magi]

Well, debate over facebook is never a good idea, more so if it's starting to get heated. But I really don't see the need for a debate over it! People are not forcing someone to tip them at gunpoint, nor are normal people running around tipping every single service provider they run into, so what's the problem? If someone likes a service they should be free to reward the provider. Almost every field of work including mine has the concept of incentives to boost productivity, how is this different, especially for those who desperately need the extra income?