When enough bad service is enough!

Where did "customers are always right" and "customers are your boss" thinking ever go? I know there is some great customer service out there. In fact I actually go to a supervisor after each great checkout experience and brag about the cashier to them. I advise anyone who experiences great customer service to do this as well. After all we want those great ones to stick around!
Today on the other hand had to be the worst customer service I have ever gotten! In fact I would call this experience a customer non-service! A few days ago we took our car into Wal-mart to get the oil changed and service done. Upon driving home my husband noticed a weird noise. We knew that we had a recall service that needed to be done on our car and had made an appt. to do so. Today we went in for our recall service and they told us at the dealership that whoever checked our air filter last busted our air filter case and it was $106. That was the weird noise and that Wal-mart was responsible to pay for it. We then went to Wal-mart to show them the papers from the dealership and they called us liars. To make this story short we are not foreseeing any payment from them!
I have slowly been shopping less and less at Wal-mart and more and more at Target over the last few months because Target has great deals! They are always clean and to tell you the truth I haven't had any customer service problems with them except once (about a coupon). O.K. I just needed to vent a little and I realized today enough bad service is enough for me and I can get great deals somewhere else! However I will still post a great Wal-mart deal if I can't find it at another place. I know alot of you still shop at Wal-mart. $30 oil changes/filter checks at a store who calls their customers liars are not in the cards for us anymore. Please feel free to share your good and bad experiences in the comment section.