You don't have to kiss anyone's ass for a tip; some people expect it, but most people just expect a friendly person to do the job they're being paid for. Don't hover around the table, interrupt conversations, even if you're trying to be polite or offer something. People go out to eat and enjoy themselves and their company; they don't know you, and don't want you to ''pull up a seat''...
I live in a casino town, and people depend on tips to pay their bills. I did at one time, too, and can appreciate that. I ALWAYS tip someone who serves me, regardless of how good looking they are, or how many times they spoke to me; I've never had someone who's rude to me, so that's why I can say I've never 'stiffed' someone. At the bars, with people who know you, toss in a buck or two into a machine, and you can get drinks all night, just always tip your bartender. It probably helps that most of these people are folks I grew up with, so I have no problem tipping them.