when you could trust your mechanic completely and they stood behind their work.
I've worked on boat, motorcycle and car engines so I have a pretty good idea of how they work. Unfortunately better than some mechanics. Twice when mechanics have disagreed with my diagnosis of a problem it turned out I was correct. The point being that if someone blows smoke about what's going on with my car I'm going to know it, if not immediately then an hour later when I have looked at the shop manual. In the last 20 years I have stopped using 7 different shops in Berkeley either for gross incompetence, outright dishonest or a combination of both. Then I found Holland Service. First off, I liked the people. I like the explanation they gave me for what was wrong with my car. Later I asked them to replace all of my brake pads they didn't do the rears. They told me the rear pads had plenty of wear left. It's a little thing but it shows that when they had to choose between making a few extra bucks and doing what was right for the customer, they put my interests first. I had an electronic control module fail after 6 months. First they replaced it for free, no charge for parts or labor. Secondly, the apologized for the inconvenience although the problem was through no fault of their own.
So bottom line, these are the first people in 20 years of looking that I trust completely with my car.