Full disclosure, I had had a few whiskeys when I responded and what I thought was written in good-natured shit talking came off totally dickish. My bad and sorry 956.
But I don't think your analogy is comparable. The guy at McDonald is punching an order into a computer, grabbing a bag of food someone in the back put together, and handing it to the customer. 956 wrote "So today at the bagel place there was one guy working, and he took the order then sliced/smeared the bagels and wrapped them up and handed them to me." So in this case, one guy is working the entire place, takes the order, makes the food, packaged everything up, etc. He facilitated the entire transaction. Bagel guy did more work. Certainly more work than a bartender opening a bottle of beer or even making a cocktail. However, unfortunately, "tipping culture" has blurred the lines of who we tip and who we don't, as well as how much we tip.
And to reiterate on my second point, if I can get a whole burger AND wings for $12, I'm not gonna complain about them not making change. Basically because I can always use a debit card. Who ONLY carries cash, and who pays cash when you can use a card? I save my cash for transactions that REQUIRE cash like tipping hellhops and airport shuttle drivers. And again burger PLUS WINGS. $12? Sign me the fuck up.