There is no "line" at McDonalds, there is simply a mob of customers, some of them waiting for their order, some of them staring at the menu-on-the-wall not knowing what to order, and some eager to purchase something and eat. Somehow that mob is self-organizing and the servers are able to "Can I help you?" the next person without a line and without starting a riot.
The one time that didn't work is when I was on a long drive returning from visiting my parents in "long-term care", and as I came up to the counter to open my mouth with my order, a group of people from what looked like a middle-school sports team after a game simply surged passed me, as much as pushing me aside. Didn't say anything but from my scowl, one of them remarked, "I bet that 'dude' is upset" only in somewhat more vulgar terms. I think I said something that I had a 'long day', was very tired and hungry beyond belief, but it didn't look like I was getting anything to eat anytime soon, I turned and left.
Before someone lectures me about my sense of entitlement, that was probably an epic fail of this "store" from their training at Hamburger U. I don't stop there but instead patronize another McDonalds a little further up the road with which I have good experience.