All hose things you mentioned Barrie, they irritate me immensely. The amount of engines that are save from doom because the starter cord broke on first start of the season. They bring it in for a starter repair, and there's not a drop of oil in the engine. They were about to use it like that.
Handle bolts, yes agreed. Threads are usually knackered because the use the machine with them loose, then of course they won't tighten up at all.
Talking of handles, Honda really should revise the lower handle fitment on their IZY's, because of the design they flair out at the bottom and dislocate. Bad, Bad design MR Honda.
Blades fitted upside down is another common one.