Interesting, because I am in the middle of a very similar discussion on another board
Something I found out today while websurfing: The minimum wage in Florida is $6.67/hour. But for tipped employees, it is $6.67 minus $3.02 (which, as required by Floridas Constitution, is the 2003 tip credit existing under the Fair Labor Standards Act) so that's
$3.65 as of January 1, 2007. I don't know if WDW pays more than minimum wage to their servers. It's true that I don't get tipped for just doing my job -- but I get paid a living wage, certainly a lot more than $3.65 an hour. I can't even begin to imagine what it would be like to try to pay bills on that.
In the US, a fair gratuity is part of the server's basic wage. They automatically must pay taxes on it, whether or not they actually receive a tip. I know that might seem wrong -- we pay so much for a restaurant meal that it seems tips should be optional. But when I plan on a dinner out, I automatically consider 15% to be part of my dining bill -- just for basic decent service, nothing above and beyond. I almost look at it like a bill at for car repair, itemized for parts and labor -- except labor is a lot more expensive at a garage than 15%

Service would have to be truly, intentionally dreadful for me to consider leaving less -- and if it was really that bad, I'd probably speak with the restaurant manager.
In other countries, tipping is often not the custom -- but service fees are automatically added on to bills, and/or workers are paid a higher minimum wage. The cost for a restaurant meal is proportionately higher to cover these things. It would be nice if restaurants in the US would just pay servers a fair wage, raising the menu costs 15% if necessary to do so -- and then if customers
wished to tip a little extra for good service, they could do so.