I like to tip if it is deserved but for me it's not automatic.
Turbo-pro has it right - if they make the experience more enjoyable they're in.
It's amazing how much variation in personalities one encounters as a consumer.
I stop periodically at a local deli to get a sandwich and when I put a buck in the tip jar, which is almost every time because they do (appreciate) and earn it, I always announce it so they know in addition to my saying thanks I am also backing it up with some cheddar.
I have no problem with tip jars. At least some folks are hustling to make a buck while others are simply content to be on the gov. dole