For those of you who don't know what the fancy looking word is in the title, it is a code of behavior that delineates expectations for social behavior according to contemporary conventional norms within a society, social class, or group. Fast food is considered food that can be easily or quickly prepared to eaten in or taken out. When you put them together, it means, this is what you should do in a fast food restaurant in order to not have the person behind make passive aggressive comments to the person taking orders about you, and to not have the entire world hate you.
I eat at a sandwich shop that shall not be named fairly regularly. Here are some rules for said sandwich shop. You have to wait in line for ten minutes to get up to the window so they can take your order. You should have been looking at the menu and paying attention to how the ordering process goes. It's not that complicated. Coco the gorilla would even call you a dumbass in sign language if she had to wait in line behind you. If you can't decide, it's a quick sub place, it's not a 5-star gourmet restaurant...get a cold cut, put lettuce, tomato, and some type of dressing on it and get the hell out of the way.
Secondly, I don't care how cute you are, if you are picking up food for your boss in order to impress him, and it's more than two subs, call in the damn order. I'm only two people away from getting my food when Sally-dipshit pulls a piece of paper out of her purse and says, I have 6 subs, one on white, one on wheat, one on flatbread, one on...I want to stab you.
Basically, fast food is fast because it's simple. Stop breaking these two simple rules and society will win. That is all.