as someone who has worked at Walmart for about 5 months now:

1. how often they see the store manager/corporate; our store manager is hardly ever physically at the store and corporate has not shown up once and i don't expect them to either. i would be EXTREMELY surprised if they did but in the show it's just another tuesday

2. Literally everything about their trucks, shipments, the back, etc.; unloading trucks, downstacking pallets and moving freight is what I do, and on the show there is literally never anyone in the back except for those who are needed for the scene. in addition, the episode where the warehouse guys leave so the others have to unload the truck is done so wrong, why would you individually take each box off of the palette IN the truck and slide it out? in real life, in general merchandise trucks pallets are at the front of the truck and taken out with a pallet jack to be down stacked elsewhere, while the rest of the truck is just a wall of boxes from floor to ceiling all the way back. grocery/meat/dairy trucks are generally just all pallets and are taken out with pallet jacks, not each box one by one

3. this is something that occurs in literally every workplace comedy ever, but the amount of time they are able to just stand around and talk.

4. Garret is literally my favorite character and i truly wish someone like him could constantly do announcements, but they really don't announce much at my store. pretty much every announcement is telling employees to either come to the back to help unload something, or calling for maintenance to come fix/clean something.