Absolutely, there are, probably, many decent exotic car owners. Given my profession, I have been exposed to them, and, unfortunately, the not-decent. Here's one example:
Chap brought in an F355 for a timing belt change. Told us not to start the engine because one of the belt idlers was in a bad way. The manual says you have to pull the engine to change the timing belt but you can do it insitu if you have double jointed elbows and a very high tolerance for pain. So I did the work without pulling the engine. Fired it up afterwards and it's making a knocking noise. Shut it down instantly and called the customer. The customer said that it wasn't noisy before.
I was super careful doing the work but I guess I must have f***ed up. Sh*t happens. Best not to take life personally.
I pull the engine and check my work, it's perfect, no issues. So we put the engine back in and fire it up again. Still noisy, of course. Do a bit of detective work and it has a bent valve on the left bank. Talk to the customer and then the real story comes out. He was driving it slowly up and down the strip, pausing to rev it up with the clutch in when it started making an awful clatter and he shut it down.
Now I'm into this thing for 20+ hours with very few billable hours in sight. If he told me at the beginning what was up, I'd have thought him a bit of an idiot and then done the work. Now? I wouldn't work on his car, period. It came on a tow truck. It left on a tow truck.