You are perhaps one of the exceptions, along with several more exceptions on here I would trust. My personal experience as a customer and professional experience is one of incompetence in industry. As professionals are so variable, I avoid them just as much as possible.
One of those extremely rare instances where I needed a mechanic for a simple job, was when I broke down in south Wales, far from home and far from my tools. I'd lost all pressure on my clutch pedal, meaning either the master cylinder had failed or the slave, so with no choice I called the breakdown out. A mechanic turned up and didn't have a clue and had to ring base for help to diagnose it, despite me explaining to him how to diagnose which had failed. There was a self sealing quick connect in the middle of the pipe, master was full of fluid, break the quick connect and press the pedal, if not pressure the master had failed simple.
The mechanics advisor back at base suggested there was an airlock - suggesting pumping fluid in at the bleed nipple down at the slave cylinder. The idiot pumped 2L of fluid in, trying to clear that 'airlock' in a system which only holds 1/4 litre, flooded my carpet with hydraulic oil in the process, before he gave up and took me in.
It took a further hour back at their base, to eventually get their base expert mechanic, to accept the master piston seal had split and get them to order up a replacement master, at £120. I had to leave the car with them for the night, whilst the part turned up and they could fit it. Given the part and the tools, I could have fitted it in 15 minutes at the side of the road - £460 I was charged for the repair alone. By then, I was loosing the will to live and just paid up.