Do shops ever fix something on the first try?

as one of those guys that can't fix anything right for the last 50 years(army and truck dealer) let me offer a different point of view. we are expected to be experts on every engine/transmission combination from the older mechanical engines to the latest ones that have particulate filters and scr catalyst using def. also be able to diagnose any electrical problem, particularly on motor homes without service manuals or wiring schematics. yes we make mistakes, sometimes our fault sometimes the customer insist that a part be replace because a friend told him that was the cure for his problem, or put a bandaid on it so he can get home, diagnostic troubleshooting trees for some fault codes on the newer engines can take 8 or more hours, at $150 an hour it adds up quick if not under warranty and with age and miles the more likely there is corrosion in the wiring and connectors causing fault codes. and as TNGW1500SE said there is the infamous $9.99 oil change
hope I didn't offend too many people with tis post thanks for letting me vent