Paul, that community is hilarious!
I actually never worked in a McDonald's, which is odd considering all the jobs I had when I was younger. Dunkin Donuts was actually the worst fast food type job I had. Yeah, I did get fired from that job - I poured a pot of coffee in someone's lap after they reached over the counter and grabbed my bottom.
I did alot of retail/banking/working with the public type jobs for many years. One of my banking jobs I had someone throw a phone at me! Yes I threw him out, yes I was threatened with being fired
OK, try to keep your equilibrium, think of this as a learning experience. This won't be easy because you are going to get rude/annoying/idiotic customers. The 'No I didn't order that, I ordered this' stuff (when they change their mind after ordering); the happy meal promos will drive you mad - I want THAT toy, not this one! The people who will pay you in change and stand there laboriously counting pennies holding up the line. The people who've been in line, staring at the menu, get to the counter and not know what they want and change their order 5 times. Oh, and don't forget the people in line with screaming children. That'll really make your day.
It seems that you'll be doing alot of different jobs from working the grill to making the meals to working the counter to cleaning. At least the McD's I go to I've seen that.
On the positive side - this is an opportunity to make a little money (yay), to learn to do different things, to learn to control your temper and your tongue and how to deal with different people. Hopefully, your workmates will be great too. That can go a long way, especially if you are having a bad day. Any job can have good and bad days, doesn't matter what you're doing. At least you'll be working indoors, you're wearing a uniform so you won't have to worry about what to wear, and I think you get either free or very low cost food - no lunch or dinner money to worry about.