Take those 23 plastic bags and roll them into little balls and put them aside. If you leave them in the sun they will bio-degrade into microscopic plastic particles to disperse back into the environment, ie. pollute the environment with stuff you can't see but ends up in everything.
Now take all of the food out of the packaging that it came in and stack that all in a pile and you will realise how little food you have bought and how much paper, cardboard, plastic and styrofoam you have purchased just to throw away. This pile will be considerably bigger than the pile of plastic bags above.
The bigger problem is the packaging. You can't buy a lot of stuff without it. The big 2 and even some smaller players get a lot of fruit and veg and meat already pre-packaged, at my local W you can't buy a single squash you have to get pack of 4 or 6. It's even worse at a couple of local fruit shops where almost everything is pre-packed.
Cling wrap and styro are not bio-degradable. This will be buried in landfill and remain unchanged for hundreds of years, or end up floating around in the oceans with all the PET bottles already there.
You can't even go to the hardware and buy a couple of screws or nails, you have to buy a packet or a box. But at least you can get a dinky little box to put your bag of screws into.