People, you need to realize that they are a retail business, much like the local grocery store. They make nothing themselves. Everything they sell is made by an outside vendor and they have to take the word of that vendor that the parts are correct. I doubt that they inspect the parts or ever even test fit them.
To those that complain about their meager discounts:
What if their profit margins are so thin that they don't have a lot of room to discount? Ever thought of that?
I am not here to defend the quality of their parts or their shipping charges. My experiences with them have been fine though.
I have never owned a business but I know people that have. Outsiders have this false impression that they are all rich, swimming in money and only out to squeeze more money from their customers.
Before your next purchase, ASK questions about the products. Learn what you can. I suspect that IF the clerk knows of a product fitment issue, they might be honest about it.
In 2003 when I bought thousands of dollars worth of stuff from Year One, I was told of defects in the door handles and possible fitment issues with seat skins. From there it was my decision whether to buy or not.