As a vendor in the industry, my feelings about tipping are quite simple:
Tip those who deserve it. Tip the vendors and staff who not only do their jobs, but do it well. Tip those who own their businesses. Tip those who don’t own their own businesses. Tip those who make your life easier. Tip the people behind the scenes; the cooks, the dishwashers, the delivery people. Tip what you can afford and remember, generosity begets generosity.