Around here it's a combination of the 2. Every single time my vehicle has been in for something I couldn't do myself (like alignments, custom-bent exhausts, and tires - before I bought the equipment) they screwed something up.
Had an exhaust system made for the El Camino. The angles were so frigged up the pipes were pointed towards the ground, vulnerable to damage, & they were causing loud vibration in the cab as they rattled against the frame. After paying the guy, I had to crawl under there & spend a half hour loosening everything up, & positioning it correctly. When I went to get tires & wheels put on before I had the house here, the guy nearly burned my power steering belt off squealing the *censored* out of it as he drove around the building at full lock .... while gunning the throttle like a tourettes patient ... and laughing about it. When I asked the guy WTF he thought he was doing, he thought I was joking - I made sure he knew I wasn't .. then the smirk slowly faded. What an *censored*! And then I can't count how many alignments I've got ...... pull out of the lot, and the steering wheel is SIDEWAYS!!
That pisses me off to no end. I have to tell everyone ... MAKE SURE THAT WHEEL IS DEAD STRAIGHT! before an alignment. Oh yeah, then there's C&R Tire in Worcester
who left my entire CAMBER adjustment bolts on my '86 Grand Marquis TOTALLY LOOSE!! I drove all the way to Phoenix, pulling a trailer mind you, before I realized what the noise was! The whole control arm was sliding back and forth on the frame over every bump! I've got a bunch more, but I'm sick of typing already.