*hugs*
We all make mistakes, Rachel. The thing to do is just what you've done...apologize, learn, and press on.

Where I live, there are two Wal-Marts within three miles of each other...and the vibe I get from them are totally opposite:
The first one is very...snooty, if that word can be used with WM. The employees will help, but their body language says you're imposing on their time. The customers are generally cold and humorless. There is a Subway that has a most peculiar odor coming from the bread ovens; not like a stand-alone Subway (which has a delicious fragrance of freshly baked bread), and it's been that way since it opened. I did mention it to both stores, but it's still the same.
The newer one is very friendly and one gets the impression that the employees are happy to see you, and eager to help (I had one person come up 3 times in 15 minutes; we were just browsing, but he kept asking in such a nice way...) Several times we've gone dancing in the aisles (when not crowded) and had customers join us briefly.
So I'd say it depends on which store (and probably which shift) one experiences. There's good and bad everywhere. (Even at Macy's LOL)