I mean, big box stores have high rooves with no sound insulation and are blasting music and ads*, the shelves are covered in brightly colored packaging trying to compete for your attention (plus more ads), they usually have terrible bright commercial lighting, there's a lot of people with large carts (and poor awareness of their surroundings) trying to get through the same spaces, and you have to find all the things you need with that going on around you.

I don't believe I've been in a Costco (or can't remember it), but the giant Walmart / Target / Kroger stores are already bad enough.

*Don't get me started on the fridges, which at one store I've been to were loud enough that I couldn't hear someone next to me.