Fitting the top bolt to the BIL when harmonising the F4 gunsight. It was a blind fit and it either went in straight away or it took forever. You needed hands like a four year old schoolgirl to have any luck with that. Of course people that I didn't know used to try for five minutes then just do the bottom bolts up extra tight...
Spending most of the night hanging upside down in the back cockpit changing and wirelocking inumerable insty boxes. This was of course after asking our best mates the armourers to take the seat pan out...they loved us.
Lots of mind numbingly boring jobs as well as tricky ones. Taking off the PFCU cover in the wheel well of the F4. Eighty squillion bolts. The chief who first showed me how to do it (or showed me the panel and told me what size socket I needed) said 'Now is the time to learn the art of meditation.' Luckily it was just the right height to be able to sit on a chair while you did it.
Virtually anything we needed to run on the E3 needed the ACE cart fitting. Used to turn a five minute job into an hour, pain in the butt.