The majority of my bad experiences have been through dealerships. The smaller ones have not been immune but--the most trusted mechanics I have found has been with smaller shops. I had found several over the years.
Here are two more stories:
Again, in this case it was with a lady friends car. The car would not turn over ... the battery died. I purchased a new battery, installed it, bam-- it started. But--it was running rough. Not knowing what more to do we took it to a dealership. I tell them what happened and what I have done so far. Hours later, I get a call. "We are not sure what is going on but we think your injectors are bad." Estimate is $1000 or more, depending on what they find. I tell them to pack up the car and we will get back to them. I make some calls to friends and I was recommended to try a small shop that they trust. I call the shop, explain what happened, and what the dealer is telling me. With no hesitation he says, "it sounds like your computer needs to be reset. With that model car, if you lose power from the battery--the whole system needs to be reset." He says, it's an easy fix and to bring it over. I do so, and the car is fixed. I think he charged me $20. Um yeah... bad injectors. Pitiful.
Another one:
I had a small Honda hatchback that in the dead of winter started to idle rough. It was so bad that I had to take it in. There was a small Honda Dealer nearby and I left it there. A few days later I get a call, "Your distributor is shot. It is loose and it needs to be replaced. Estimate... $1800. I call my Dad and he says to bring it over. We pop the hood, I reach for distributor cap and it is loose. Dummy me--I says--yeah look --it is loose. My Dad says, "yeah, hold on. Let's look closer." Further inspection revealed the distributor was fine. Yes, the cap was loose--but it was probably from the dealership monkeying with it. My Dad quickly figured out that we needed to install a new cap and rotor. It was a few dollars of parts. Bang! Car is fixed.
I have many more. My Dad had several horror stories from an Olds Dealer that were downright fraudulent. My Dad always ended up fixing it himself because he was onto their lies.
Now a days--I drive a Ford and thus far--I have had good service from my local Ford dealership. I had one incident that was suspect--but it didn't cost much--and I am willing to give them the benefit of the doubt.