Cashier comments on a purchase? Who gives a shit? Buzz through the line with your stuff then leave. This is how to handle it: "those are good fig newtons and/or Great Value hot dogs are just ok" My response: Yup....see ya later. Done.
"NRA FOR LIFE" T-shirt would stir up the liberals. Seriously (if you can believe that) we had no problems with folks wearing red and khaki. Go with the rules, no need to buck the system as it will only make things more difficult.
How far in advance of your shift did you call out? Did you use the phone? Did you talk with HR, TL, ETL? Do it verbally and document names, times, content of conversations.
I bought a T-Fal square griddle at the big T, gently cooking any meat almost permanently stains the surface. What's the secret? More thorough seasoning?
Biggest problem I had as a trainer (for a year) was many new hires didn't focus and were addicted to their phones. Most had the capacity but many didn't have the fuel and drive to learn. It was frustrating.