Hi, I worked in a kitchen at a small pizza restaurant. I've also worked as a waiter and a pizza delivery driver.
Alright, one thing, first day of a job, it's okay to get there fifteen minutes early, it's okay to get there 5 minutes early. So, early if possible, but not uncomfortably early.
I do not like being criticized. One time at the pizza place, the guy criticized me for taking too long to clean up water which has gotten onto the floor of the walk-in cooler when he had no idea how much water was on the floor. It's like the person is less engaged than I am, cares less than I do, and still criticizes me.
The zen approach is just for me to care less. I show up on time (or slightly early) and I show up sober, and everything past that is a bonus. A good medium rate of speed, and I will make mistakes, that's okay. You can even criticize me for mistakes. So, I go medium, I get into the flow, and thus I'm more ready if we really get busy. And if 100 is the official maximum speed and 110 is the real maximum we can handle, I try and give them a brief heads up at 90, 95, etc, without overdoing it. A lot of bosses just don't want to know, it really is amazing.
If you get hurt, please sit down. The act of sitting is a physical statement that you really are hurt or sick. Please don't let them bully you into continuing to work, which I have went along with when I've been sick on a couple of occasions. And when standing and working at a counter or table, maybe put the front/side of your hip against it kind of as leverage and to help preserve your back. And please don't work so fast that you get hurt.
PS An interesting story, a guy was telling me about his brother who worked at a grocery store. And the brother cursed out his boss, but he did not get fired because he was a good worker. Later when he calmed down, the boss just told him, hey, when you get upset, try not to say all that. Not that I'd recommend it as any kind of percentage move (!) But just goes to show you that it's a crazy world.