Which grocery stores sell good sandwiches?

While there are plenty of sandwich spots across the nation who cater to your hoagie needs, your favorite sub can also be found in your neighborhood supermarket.

...

Wegmans overall had the best taste and value, in my opinion.

Whole Foods.

Harris Teeter.

Trader Joe's.

Wegmans.

Winco sells some really good large subs.

I always think gas stations deli does but then Krogers is the second best....

Shoprite and wholes food and bjs and Costco. 

Assuming you mean in Los Angeles (as this is posted in Los Angeles Dining Out), the city is big so it depends on where you are. It will take you an hour or two just to get to some of these depending on where you start. 

If you are in the South Bay by all the beaches, I’d recommend Jackson Market and Deli. Good italian sub and panini. If you are downtown I would suggest the Eastside Market and Deli. Get the DA special. If you are up in the valley you can’t go wrong with the Tarzana Armenian Deli and Grocery. That’s some good stuff. 

Probably the krusty krab. They've got good reviews.

None. Pre-packed sandwiches all use the full across the diagonal trick. The rest is nearly empty but as the cut it diagonally and pack it with that edge showing, they always look much fuller than they really are.

The top three sub chains in term of sales in America are Subway, Jimmy John's, and Jersey Mikes, according to Nation's Restaurant News.

"good" is a personal preference.  For me, Harris Teeter sandwiches are good especially for the price.  (Deli sandwiches made to order; not the pre packaged ones.)

Whole Foods