I don't feel bad about not tipping (if I don't have cash on me). These days, I hardly carry any cash with me anyways, and with barely enough time off to run to the bank on my days off, it's not at the top of my priority list to get dollar bills for the van drivers. Especially considering all the other concessions we're taking...

I do tip the good ones though for good service if I have a buck, but they have to be friendly and not act like they're entitled to the tip. It's a courtesy the way I see it, and if they need a bigger salary it ought to be negotiated with their employer.

Besides, I grew up in Europe... no one (aside from foreigners) tip over there, so I don't feel bad for not doing it if I must. I just look them in the eye and say: "Thanks"!