Setting up the searchlight on Nimmy's - far too many volts waiting to hit you on a damp Scottish night shift if you didn't locate your screwdriver exactly on the potentiometers while wearing 3 layers of arc welding glass to stop your retinas getting scorched
Another was getting the Herc Tanker HDUs set up, alas we didn't have a "gag" in ASI so had to do it while airborne rather than on the ground.
I've done & hated both those jobs !At least when adjusting the searchlight you could get a tan !
Loathed replacing the ADD probe on the Harrier (GR3),upsidedown in the cockpit,one handed at full stretch,hot & cold - lovely!