Gratuitous

I recently was reading Slate and saw the article on Starbucks and saw about how the key to "Starbucks happiness" was to tip well.
Since I'd consider a Barista something of a non-alcoholic bartender, the idea of tipping them seems appropriate. But then again, I haven't had reason to tip at a Starbucks in a long time. It's become something of the ghetto-coffee-house. One near me is so low on inventory it's like the Monty Python Cheese Shop sketch. Others have non-english, non-spanish speaking employees and you get whatever they happen to throw at you. You have no idea what you'll get when you order even a simple Iced Tea. Yet others sit and visit with each other ad nauseaum to such an extent that from order to finished product can take no less than 45 minutes.
Needless to say, I don't tend to tip. Actually, I don't tend to go to Starbucks anymore. I find Caribou to be a better option and Bad Ass to be my favorite. There I tip.
But on the subject of tipping, does anyone find tip jars appearing in places you think are completely inappropriate??? For example, in the drive-thru window of Dunkin Donuts??? I used to work in food service for a long time and know that waitresses live on tips. The wages they get from restaurant work are roughly 1/3 minimum wage. Also, waitresses are often called upon to perform other duties in a restaurant: janitor, sommelier, etc. Donut employees and their ilk make minimum wage. They don't have a gap to make up for and .
Bartenders make tips because, while they don't have a gap to fill, they have gone to school to learn their trade. Being a good mixologist is an art. And like waitressing, their focus is customers, service, and to a degree far more than required of fast food.
And if one would begin to start requesting gratuities, wouldn't it make sense that the most basic of customer service (getting orders right) would need to be fulfilled?
I realize that there is often a language barrier in my area (I don't speak Farsi, Urdu, Hindi, etc.) but I still am not tipping someone who give's me a strawberry jelly and cream cheese bagel when I asked for hot chocolate.