I agree that a lot of so-called professional work is sloppy (about 1/3 in my experience) but learn to have a little sympathy for the guys doing the work. When you're in your own shop, you work at your own pace and are free of distractions except any you allow. The guy at the dealership is under time pressure, gets interrupted, etc etc so doesn't have the advantages you do. Remember, the guy with the wrenches is coping with everything that comes in that front door and that can range from the silly simple to the incredibly difficult and he's only getting paid for his work which is tiny part of the bill you get....
When you find a good shop make sure you know WHO does your work and let them know you appreciate their efforts. One of the less thrilling things about being a mechanic is working without a lot of direct human interaction and I think you'll find many of the guys appreciate a favorable comment or two. Besides, you can learn a whole bunch by asking a few well thought questions.