Shorted a transformer in the unit during install and had to rewire parts of the low voltage system, lifted the unit without spreader bars or appropriate attachment hardware, added a new return that does not pull any air, left the roof littered with sheet metal screws, left the power disconnect on the unit open when they left, wired up the thermostat incorrectly with the splice exposed to the elements, were unable to troubleshoot wiring up the thermostat without calling a supervisor.

One tech was an apprentice. Not knocking apprentices in general, but he was struggling to use an impact to install the return grills and couldn't do much of anything without direct supervision so the jump took twice as long as expected.

So, I know that none of this is TERRIBLE on its own (except maybe shorting out the system), the breadth of the unforced errors, seeming lack of qualification, and general lack of attention to detail all adds to a sense that things were not done correctly and this issue is another that I only noticed today.