Once I ate a half eaten snickers bar that I estimate was forgotten in my car about 2 yrs . I don't care
No rules here . Cheap mozzarella , cheap olive oil , and cheap coffee won't make my basket , but anything else doesn't matter much .
I can eat pizza that has been in the icebox for a week If I am hungry and tired , it's ok
My criteria for choosing a supermarket : who has the best fresh flowers ? Who can get me out of there in 10 mnts tops ?

I don’t eat fake food, for example, margarine.
But since now all I can eat is whatever will stay down, I’m nowhere near so picky. I get what I can eat, afford, and have the energy to prepare, eat, and clean up after, if it must be cooked.

All of the above. When I lived in AZ I remember seeing something called 'cheese flavoured block'. I nearly vomited. Processed food is flavoured, salty, fatty sawdust and is terribly unhealthy. I prefer to buy fresh everything. Its easier here because the local market is still fairly good.

Anything I have to cook.

I will never buy Grated Parmesan cheese.I only buy chunks of it and grate it when needed .Tastes 10 times better .Will not buy canned vegetables or white sugar.

Bottled water

it depends on how hungry I am

I must admit that I do a lot of politics when I'm at the supermarket. I do my best to change the face of the world for the better whenever I buy something. I try as much as I can to buy local products instead of imported ones and to encourage small businesses instead of some mega-multi-national corporations.

Too much to list. I cook at home from scratch.

From June to November, I go to the Farmer's Market on Saturday mornings for fresh, in season, fruits and vegetables.

So I don't buy:

Processed foods.

Ground beef, preserved or processed meats (chicken nuggets, bacon, ham, sausage, etc.) deli meat, beef or organ meats.

Other unhealthy crap that Americans love.

Pretty much everything on their shelves. About the only thing I do buy at a supermarket is pasta noodles, rice, milk, during the winter veggies and I check country of origin on them and an occasional pre-made large cheese pizza which after a remake becomes a deluxe Pizza.

I am with you there. I try to read the ingredients on the back and see how much sodium and sugar there is too.

Any of the ready meals. They taste crap and are expensive for what they are. I’d rather have beans on toast if time is an issue.

The copious amounts of chocolate and biscuits, meat because I don’t eat meat! Thinking about it,I don’t actually buy much at all!

Farm fish from China

Easier to say which I only buy, fresh produce, meats, poultry, seafood and dairy products. Freshly baked bread. That is about it.

I eat gluten, grain and dairy free.
About all I buy at the store is chicken, vegetables, fruit and toilet paper.

Pre-formed burgers? But you eat red meat? Are you high?
I'd never eat it, or any other kind of meat (pork, chicken, etc.), but I do eat small fish like sardines. And fermented milk. And cage-free eggs.
It'd be a LOT easier for me to list the things I DO eat from the supermarket. Most of it is pure poison.

Bread

Being an old guy I was raised in the country where people had large gardens and when we were kids many days during the summer were spent picking peas, beans, corn, etc and then shelling and shucking. My mom would spend days at a time preparing them for freezing. I find that buying fresh vegetables and fruit from the grocery store is a waste of time and money because they just aren't good. Probably because most are picked before they are ripe. Even some of the roadside markets here have vegetables and fruits trucked in from the southern part of the state (Georgia) and Florida and they are not ripened on the vine. I end up feeding most of my purchases to the bear, deer, and other wildlife. Also I find buying and cooking food for one person is an art that I will never master. I love watermelon and in the past six years I have probably bought and thrown away 20 melons because they are garbage. So to finish up this long story, I purchase mostly frozen fruits and veggies. I'm with you on the processed meats however I do purchase a pound of bacon about once a month as a treat. Those fresh vegetables and fruits are the only thing that I miss about living in Louisiana and since I love living in the mountains that's a sacrifice I'm willing to make. That probably explains why I weigh 20 pounds less now than when I graduated high school.

booze

Canned goods mostly..seafood..prepackaged deli meats..

I do not buy organic fruit that must be peeled . This is a waste of money . I will not buy cheap balsamic vinegar or reconstituted orange juice . Rarely buy soda.I despise canned vegetables.I do not buy anything in the big name supermarket that I can get in the family dollar store ,as an example a dozen brown eggs for a dollar in the dollar store . Will not buy powered garlic or garlic salt only fresh . I will not buy olive oil unless it is extra virgin oil.

Toxicity limit of packed or canned food is not reliable. Everything we surrender to the market.

I don't buy ... meat, eggs, bread, fruit, tinned fruit, tinned soup, pies (fruit or meat), very little in a supermarket that I buy to eat ..... almost everything I eat is grown or caught by me, or bartered / bought direct from local farmers / growers or small local shops
From supermarket I buy baked beans ... but I occasionally make a couple of gallons of boston baked beans and freeze what isnt eaten straight off
and I buy milk ... there is no dairy farmer close by, but I collect cow fresh whenever I pass by there.
I buy - toothpaste, mouthwash, soap, etc.

Anything GMO free, I’ll take all the advances of modern genetic engineering if that’s ok with you.
...
With the exception of this one strawberry lemonade that’s PACKED with sugar and perfect to mix with Vodka