I bring it back to the store, like a proper child of the light.
EDIT - ProTip:
Leave your reusable bags in your car. When you checkout tell them you don't need bags and to just put the groceries back in the cart. You can bag the stuff at your own pace once you are back at your vehicle. No self bagging stress, no "I forgot the bags stress, no extra work for the cashier, no need for a bagger, and you help the queue move faster.
Nah, the Stop n Shop I go to has portable scan guns, it's really the best. If I have to shop somewhere that doesn't have these, it will ruin my day. For the uninitiated, it's a portable bar code scanner with a little screen on it. You scan items as you take them off the shelf, put them in your bags, and when you are done shopping there is a "checkout" button on the gun/screen that generates a barcode. Scan that barcode at the self checkout, pay, and be on your way. It is peak grocery shopping efficiency.
Some stores (where I live) have the scanner, some use an app to scan. Works the same but they don't need to maintain the scanners with you using your phone. Finding a store that doesn't have the option to scan as you shop is quite rare nowadays (where I live).
We keep telling you that you cancel all that goodwill out when you give the cashier The Look and announce there's no need for bags and that you're putting it all in your cart unprotected.
Before I moved here I used to think temps in the negatives were crazy, but you really do get used to it. Plus, good cold weather gear makes a huge difference.
I'll tell you what's crazy, the 95°f+ with 90+% humidity we used to get in Louisiana. There's no getting use to that. I don't miss that one bit.