I trust my Ducati dealer. They do excellent work. They have never damaged my paint, failed to complete requested work, failed to do proper work or used an impact wrench when a torque wrench was needed. I trust my local mechanic for the Challenger. I trust the Subaru dealership for my DD. I think it is a bit of a stretch to assume everyone who has an issue with a dealer some how caused the issue by getting what they gave.
That would be a stretch, but it's not what I said. There are some dealers who are not up to par, so I think it's a stretch to assume that that means there are no good dealers, which you didn't say either. I have seen the way some people act toward dealerships while in the shop acting like an ass. And I've seen posts from some people insinuating the professional mechanic at the dealer is nothing more than a trained chimp. I can only hope they get what they give... karma baby!! My original comment started with "I must be the luckiest guy in the world.", because I've not had the bad dealer experience that apparently so many others have if posts on the web are to be believed. As a retired mechanic, I know we're all human, mistakes are made and accidents happen. It's how the mistakes are handled that matters most, to me anyway.
Actually, my original original comment was that I solve this over done issue of what is the correct oil to use by taking my car to the dealer.