[troutman]

Tipping:

http://en.wikipedia.org/wiki/Tipping

The customary tip for a restaurant meal in the United States is 15 to 20 percent of the bill.

When at a bar, and receiving good or above service, it is customary to tip $1.00 per drink.

Tipping in Canada is very similar to that in the United States due to the relatively close nature of the two countries. However, tipping is less widespread and generally lower. For example, while the tipping range for waiters in the United States is 15-20% with 20% for good service, the range for waiters in Canada is 10-20% with 15% for good service. Albertan tip earners generally receive gratuities on par with the American level, perhaps owing to that province's increased affluence and closer cultural ties to the U.S. Quebec and Ontario allow employers to pay lower minimum wages to workers who would reasonably be expected to be receiving tips. [7]

Workers who receive tips are legally required to report the income to the Canada Revenue Agency and pay income tax on it. However, many workers have been known to not report any income from tips at all or, perhaps more commonly, to "lowball" the figure. In response, the CRA has vowed that it will closely check the tax returns of individuals that it would reasonably expect to be receiving tips to ensure that the tips are reported, and that the amount reported on the returns is realistic.

Origin of Tipping:

http://www.straightdope.com/classics/a1_333.html

Taxi drivers and waitpersons depend on tips for a substantial part of their income. If you didn't tip, presumably they'd expect to be paid more, and your restaurant bills and taxi fares would consequently be higher. The fifteen percent standard is mostly a question of what the market will bear. In New York, the figure these days is twenty percent; European restaurants generally add a ten percent gratuity to the bill.