Sometimes we have to admit to being human. Sometimes we try as hard as we can to do things right and yet still we fail. Think of all the adages about the subject. "If at first you don't succeed, try, try again." "When the going gets tough, the tough get going." "You have to kiss a lot of frogs to find a prince." And then there's Murphy's Law, which states: "Anything that can go wrong, will go wrong, at the worst possible time."
I could keep going, but we would both become depressed, so let's explore some ways to avoid failure. We all have experienced car repairs, which have not been successful. By that we mean the car still had a problem after a repair was made. When this happens it often triggers a human response known as the "Rip-off" reflex. We are simply certain that the repair, which was made was not necessary, and we not only want our money back. But since he failed to find the problem, it magically becomes his problem, rather than ours. He can pay any future towing bills or diagnostic charges, or even future repair bills from other repair shops. Does that sound like a stretch? How about people who sue doctors for not finding their ailments? I'm sure that neither you nor I would do that, but some people do. How do doctors protect themselves? By ordering lots of tests. Guess how mechanics do it. No, they can't order MRI's, but they can use what we call the shotgun approach, developed and polished at new car dealerships.
You take your car in because it has a miss in the engine. The problem may be only one spark plug. A new car dealership will tell you that you need all new spark plug wires, ignition coils, fuel filters and fuel injectors cleaned, new belts and hoses, new oil and filters, and oh by the way all new spark plugs. This repair job will not be a failure, because there will be no miss when it is driven away. The "Rip-off" reflex will not be triggered because the miss is gone. In the eyes of the owner, the tech is a winner.
In the first case, a possibly unnecessary repair, although not expensive, causes a massive negative response, and in the second case, many unnecessary and expensive repairs were made, and there was a mild response. Since mechanics are trainable animals, you are training them to overcharge by over-repairing. There is another option. Simply allow your tech to locate the problem or problems at a slower, more methodical pace. Many times there is more than one problem, and one has to be fixed first to isolate the other one. It will cost much less than replacing every possible culprit on the car, but it might take a little longer, and require a little more patience on your part. Nobody likes being a failure. We all want to win, but we can't win all the time. Think about sports. At the end of the season, only one team is the winner, all the others are losers, but they're still good athletes and they played hard.
A good friend from Argentina told me, referring to their war with England over the Falkland Islands: "It was our first war, so we think second place isn't bad."
Keep smiling. It makes you feel good.