I used to go to a gas station that was in easy walking distance from my house. I asked him to change my muffler and he called me at work to tell me the price for the muffler and pipes. When I picked it up he said or I asked and he had not replaced the resonator. He said, You don't need that. I said I want it and he thought it might be in the trash behind the station. But it wasn't. Admittedly the car was not that much louder without it, but he should have said what he was NOT replacing, more important than what he was.
Later I wanted the wheels aligned and he had to call someone to find out how to do it. Now alloy wheels are very common, but even then my car was about 10 years old so they weren't a new idea. He was told to put wheel weights on the rim to attach the device and remove the weights afterwards. He should have known that.
Then he made a 3rd mistake -- I forget what it was -- and I stopped going there for repairs, even though no other place was as close. Fortunately they tore the whole shop down and put in a convenience store so I'd have to stop going there anyhow, for repairs anyhow.