I usually don't.
I've gotten to be fairly regular at one place though since we moved. The more I get to know the guy behind the counter, the more guilty I feel leaving the store without tipping him - so I have been tipping him.
It's ruining my morning coffee experience. I can justify 20 bucks a week for my morning coffee and bagel, much more than that though, and I'm going to have to reconsider brewing a pot before I leave the house.
![Smiley: glare](http://zam.zamimg.com/i/smilies/glare.gif)
An aside: Retail counter workers make, at least, minumum wage. Wait people are paid significantly less/hour by the employer (I believe minumum wage for tipped employees is somewhere around $2 - $3/hour). Also, I was a waitress for years and so, tip waitstaff very well.