I say it a lot and I'm only half joking when I do, "I'm the best mechanic I know.". Like to caveat that with the fact that I don't actually KNOW everyone on this board and I may or may not have temporarily replaced a thermostatic fan switch with some 12-2 NM household cable wired to residential light switch in the cab...
Still, I don't always have the time or desire to do my own work on things like gasket replacement, flush n fill, wheel alignment, etc. I actually bought the factory service plan on my daughter's new car so I wouldn't have to do it. For my Jeep, it sees another mechanic once a year at inspection time- He always gets paid for tire rotation, oil and filter change, flush n fill for all fluids, air filter, etc. Not because I can't do those things cheaper, but because nobody makes money on inspections. So, he can do my inspection some quick general services and make enough to cover his time. While I trust him, I don't feel like paying $120 an hour for most stuff.
The dude that put that shit on your Jeep should be taken out back and beat with a 10MM box end at 1/2 hour intervals.
I've run across his kind so much that I don't trust any shop to do real work anymore.
My short response to them is still generally, "Fix it or I will cost you way more than the cost of the job." Most of them don't care. If they have a good location, they'll get plenty of business and you won't really hurt their bottom line that much. Still, I feel like I need to protect unwitting people that might go to them unaware of their shoddy and dangerous work.
Sorry for your luck. Now you know. The dudes attitude might make me make him my special mission for about 20 hours of work to get all my money back plus the wasted time. I dunno, I make pretty good money so I'd really hafta evaluate if I wanted to be a pain in his wallet bad enough to do the work.