One thing I have managed to drive into my own head along the way...if you arent watching them... repair shops will NOT do a great job, or as some pointed out "any work at all". That olde scam of "The insurance regulations forbid customers in the work area" should read... "we dont want you watching and seeing how little we do or know". If the shop will not allow you to watch the work being done, from a reasonable area now, I would highly recommend you leave and find one that isnt intimidated at you watching. Now you may also want to learn to keep your questions until after the work is done... damned pricy to talk to a 100.00/hr tech as he works on your rig and your distraction is NOT going to allow him to do his best. It will amaze you how many times you are paying that 100.00/hr rate, along with several other customers, only to have the tech get confused as to what exactly was done on which unit. Distractions are the bane of repair techs so save your questions and concerns for after the job is supposedly done. BUT DONT BE AFRAID TO STOP WHAT YOU FEEL IS WORK THAT IS CAUSING DAMAGE OR NOT AT ALL WHAT YOU WERE TOLD WAS BEING DONE. Very often the communication between the tech and the service writer leaves a lot to be desired... when the repair order is being written up make sure the service writer states on the order any customer demands or expectations, that way it reinforces to the tech what your desires were/are and there is fewer chances of screwups. You would go into shock to learn how often the wrong oil or wrong brand is added...and after the fact all of the shop personell will swear they did it other than you may have observed. Do not hesitate to go to the shop manager or even the "Front Office" if there are conflicts or doubts. I have watched techs add the wrong oil, even after it was printed in capitol letters on the service order... once had to have Chevrolet in Detroit step in to resolve the issue after the service manager told me the owner's manual and I were suffering from extreme ignorance.
A wary eye and a questioning attitude will often ward off poor performance... remember "it's your money and your rig" that tech or service writer won't be there when the rig quits from poor worknmanship ! Been there, suffered all the indignities ya can imagine, now I question and even issue STOP WORK ORDERS when I know what is happening is NOT what I expected or was told would happen. Stay advised, READ your Owner's Manual, know as much as you can about the job before it starts.
Stay safe and enjoy this awesome lifestyle !!!