Well, talking about stoopid things, I can jump right in
(no, I won't mention any gear shifters
this time
). I changed the water pump on my 1.9 Kadett two weeks ago. To remove the radiator, you better take off the hood release first, to slide it up and out. I bet ya'know what's coming, the thing that was forgotten when closing the hood was to reconnect the stoopid hood release. I kind of remembered 0.01 seconds before the "dang" sound the hood makes when it falls into the catch - of course too late to catch it. Fortunately enough, you can pretty easily pry a Kadett hood open with just two regular screw drivers, one to crack up the hood a little, and the other one just needs to be pushed in onto the release latch ...
Dieter