I don't mind drum brakes but hate doing them on multiple makes each with their own way of doing things.

It seems like everyone has their own way of fixing wiring and everyone seems to complain about everyone else doing it the wrong way.

I hate working on a car that someone else either already started working on before and left things apart or didn't put them back together properly.

And it's more of a picky thing but I hate seeing something that's been restored or even worked on before where someone randomly threw the screws and bolts back wherever or replaced them all even when they didn't need to me and didn't bother trying to match the existing ones. Both in appearance or size and type.

I don't mind body work but being an amateur at it it bothers me when I can't get it looking perfect and annoys me, mainly on cars that are being driven and not restored, spending time on body work only to have it start rusting again or paint peeling or whatever else.