I'm the same way. Not because I worked there and was treated like shit (although I did work for a company that didn't treat it's employees well...which I'm happy to report that karma bit them in their ass as they went bankrupt and were brought out by another company)

I had a sour experience with them as a customer. I had bounced a check there ten years ago. I was only 18 and I was learning the ropes about having a new checking account.
A quick background: Whenever I got money, I had accidentally put the money in my savings account rather than my checking account (at the branch I was at, there were two separate numbers you had to put down if you wanted money to go to checking or savings rather than just one account number where the money can go straight to your checking account). So, I had the money but not in the right place.
When I went to the Wal-Mart back home to give them the money I owed them, they wouldn't take it because it wasn't the Wal Mart I bounced my check out *cue me with a dumbfounded expression*. So, I had to get a money order and send the money to the one I bounced my check out via the post office.

On top of this, one of the things I had brought with the bounced check was a CD player...that broke a month after I brought it. My thing is that they have shitty ass products and if I want to buy something, I want it to have good quality and can last a long time.