If it makes you feel any better....
I always take my car to the dealer and TELL THEM what's wrong with it.
They never trust me, they never believe me, and while I can see their side of the coin, they must follow protocol and trouble-shoot my symptoms from scratch. This is especially true for warranty issues as they must document everything.
But when I'm in a hurry to get my car back ( which is of course, always ) I will actually call the parts desk and order the part(s) under my name a few days in advance. Since it is a Hybrid, most things are not "in stock" at your local dealer.
Example. I knew I needed a new electric water pump. So I ordered one a week in advance. When I took it in I told them I need a new water pump.
"Oh, that's up for our tech's to determine, but we'll be happy to check it out."
4 hours later I get a phone call:
"Yup. You were right, you need a water pump. We're going to have to order one. It usually only takes 3 days to get a part like that. We'll call you when your car is ready."
Me: "Check the parts dept. I'm pretty sure you have one in stock."
"Ummm.... okay... but I doubt we have something like that."
I picked up my car 2 hours later. 1 day service.