A little piece of advise
We mechanics are human beings, too. We can and do make mistakes. True, there are a whole lot of hacks out there. But there are plenty of us who really take pride in our work and do the very best we can. But things happen. In my 8 years as a professional technician ( I am 23 now), I have had my share of oopses. I have been at the same shop for my entire career and have worked on slightly more than 12,300 cars (often the same car more than once over the years, but that is the number of invoices with my name on them). That is not as astronomical an amount as it sounds. That is 5-7 cars per day, 5 days per week. In that time, I have had one wheel fall off, three times a loose caliper bolt, a few other bolts that did not get tightened on water pumps, diff. covers, etc. and 2 times had oil caps off. All total, maybe a couple dozen major problems that were my fault. That is an error rate of ~ 0.2%. Yes, the stakes are much higher than the office clerk who forgets to fax a copy. That is the nature of the beast. Find me a career where mistakes are never made.
Also remember this; Eeven the very best mechanic will not find every problem on every car. There are simply too many systems and components on modern automobiles. This is why it is crucial that you be brutally honest about everything that is going on with your car. Withholding information will not save you money, especially in the long run. Would you not tell your doctor about a symptom hoping that it will just go away?
I understand how frustrating and infuriating it can be when your car is one of those that makes that .2%, but try to look at the bigger picture. Forgiveness is divine. MOst decent shops will be more than happy to repair the problem at no charge and reimburse you for additional expenses incurred. We will usually throw in free oil changes and the like as well, depending on what the problem was.
Lastly, keeping in mind what I have said, try to get any major repairs done well before you go on a long trip. Don't put it off till the last minute, where you could be hundreds of miles away when the problem surfaces. I can't count the number people who want to get everything fixed on the friday of a holiday weekend before they head out of town. Bad idea. Oil leaks, coolant leaks, etc., are often no big deal when your still in town. You notice the problem and take it back, the shop fixes it. But when your halfway to BFE it is very inconvenient for you and equally frustrating for the shop. Trust me.
PS.-two things to never say to a mechanic shop when you do not want to do the repair work. Don't say "I'm selling it". We only hear that about 15 times a day. Just be honest and say you can't afford it or don't want ot fix it, or want another opinion.
And the most insulting thing you can say to a shop that has taken the time to inspect your vehicle:
"I'm going to have
my mechanic fix it"
That is the biggest slap in the face, and they are not likely to be very helpful in the future.
Oh yeah, "I can get those parts for way less". Duh. Auto shops are a for profit business. We sell parts at list, not retail. Would you go to a restaurant and say " I can buy that steak way cheaper than that"? Don't think so.
OK, rant off.