S/O fast food etiquette

I understand your frustration, but as someone with a hearing loss I find your action appalling.

Why didn't you tap them on the shoulder?

I agree and it doesn't matter if it's in a restaurant, grocery store, movie theater or on the road

I feel like some sort of out-of-orbit satellite in those situations.

There is no 'pick up counter' in some of these places, so you are supposed to step back to.... where?

Out of the way of those who haven't ordered, of course.
Next to the catsup and napkin bar?
Over by the exit?

You look like someone who is waiting in the order line, if there isn't much room.
So people are all, "Are you next?" you're all "No, you go ahead, I've already ordered."

We went to a free magic show this past Saturday that was held in the town square where we live. The city hall has an open area in front of it where people can set up chairs and the entertainment performs on the steps of the building. The events are often very popular for families, especially when the weather is nice like it was. The square is surrounded by retail and restaurants and draws lots of people outside of events as well. There is a Starbucks directly across from the square that gets very, very busy. The staff often have to do cleaning tasks even when there are lots of people in the store because it is just that busy.

I went in there Saturday, ordered a hot tea, and then went to the side bar (which is kind of tucked into an odd corner) to get Splenda. A young employee was there, changing the trash bag in the container that sits under the counter (where the trash goes after you throw it in the opening). I waited patiently, knowing it would not take long for him to finish pulling the old trash, re-lining the can and then placing the can back inside the counter. I watched no fewer than 3 people squeeze past me, and the poor guy trying to do his trash duty, just to reach sort of around the employee so they could get a stir stick, sugar packet, or whatever else it was they felt the could not wait 15 more seconds for. The poor employee ended up having to stop what he was doing all three times just to make room for the jackasses.

When did life get so busy that people can't wait patiently for their turn?

I agree.  In N Out Burger is so loud that sometimes you can barely hear your number being called 

Oh I've seen it when visiting my cousins in Ontario....

Tapping on shoulder is assault? But deliberately stepping on someone isn't?

IME, many cases of "rude" behavior are unintentional on the part of the person exhibiting it. For example, I have been standing in someone's way and have been quite unaware of it-nothing intentional, that is for sure.

as for saying excuse me, I am pretty young to have hearing loss, but I do. I often truly don't hear someone speaking to me-especially if they are not directly in front of me.

I tend to assume people don't mean to be rude and go out in the world acting as such. it leads to mostly positive experiences with my fellow man

When they called your number you could have replied (very loudly) that you could not get through to the counter, could they please bring your order around for you. I think this is partly the establishments fault, one of the workers should politely ask the customers to wait to the side rather than blocking the counter.

I totally agree with this line of thinking. I prefer to give people the benefit of the doubt too. I really don't believe most people are trying to be rude. Sure there are a few people I know who go through life only seeing things from their own perspective and not caring much about their fellow man, but most people are simply trying to get by. Or are in a hurry.