You can feel their exhaustion as they look down at their child and ask them which kids meal they want. As they order and pray to god that the restaurant gives you the right toy, you know exactly what they're thinking: "Please God! Let this buy me a moment of silence." You have the brief judgemental thought that when you're a parent you'll never let your kids eat anything as unhealthy as fast food. In your head, though, you know the truth: when the time comes you'll do exactly what this parent is doing.
Accompanying the parent is the one person in the restaurant that doesn't have a tinge of sadness to them. This kid is happier right now than you could ever hope to be. He's been waiting for his mom to break down and take him for nuggets fo weeks now, and it's finally happened. For a brief moment, you see the world through their eyes and start to remember the joy that these places once brought you. Then you look at the rest of the customers and remember the truth about your current situation.
Look, I get it. I'm as miffed as the next guy if I ask for a plain burger and bite into something with mustard and pickles. That said, I know what I'm getting into when I go to get fast food. This person clearly doesn't. They seem to think that the dollar they're spending on a small fries guarantees them the finest service in all the land. They give the worker some obnoxiously intricate order, and expect absolute perfection in return. There's a line between ordering what you want and being a dick, and this person has long since crossed it.
After a night of binge drinking, this dick decided to get some food before only eating half of it, and passing out with a chicken nugget in their mouth. They are clearly having the time of their lives and everyone HATES them. They act like they the entire restaurant is there solely for their amusement. They scream, order a shit ton, and leave a huge obnoxious when they leave. You'd judge them SO hard....you know, if you hadn't been in their shoes countless times before.
Much quieter, but no less annoying. You stand in line behind them and wait as they try to wrap their head around what exactly a bacon cheeseburger is...like, how could they be made of pigs AND cows? Whoa. You won't enjoy your order anywhere near as much as they will, but that doesn't mean you want to wait for their stoned ass to make it.
What's this guy doing here? He's wearing a suit and making some sort of a business deal on a bluetooth headset as he orders a very undignified chicken sandwich. He seems so out of place....like, is he just here for the convenience or did he like....plan this meal. You can't wrap your head around it.
Aside from that last guy, nobody in this restaurant is living their best life. That said, there's always one person that stands out above all others as "the weird one." This dude seems is wearing three pairs of glasses and a monocle, smells like a butt, and he seems to be smuggling a live chipmunk in the front pocket of his pants. Eating your hamburger becomes infinitely more unnerving with him staring at you intently, but...I dunno. You're already here. You might as well finish.
They're probably there by choice. They probably like the food they're standing in line for. They're probably very happy in their life. It doesn't matter. When you see them, you can't help but see yourself in them and think "God, I hope I'm not going to fast food restaurants when I'm their age." It bums you out to no end.
...I need to learn how to cook.