Here is how I see it, I tip if something in the service is above what can be expected, in my view one shouldn't get tipped for doing their job. Of course if a pizza delivery (Very rare indeed where I live, we always go ourselfes to the pizzaplace) person would go in the snow etc of course I would tip him/her but don't expect me to tip someone for just doing their job. I tend to agree on this issue with one of the guys in Reservoir Dogs on this issue