I have finally come to the conclusion that instruction manuals come impregnated with a toxin that radiates from the printed page and enters ones brain through the eye. This is an amazingly potent chemical that induces sleep within minutes of starting to read the manual. In some of the hardier persons around, when sleep is not induced, it causes great confusion and ensures numerous attempts to turn back pages to re look at diagrams and seek out annotated functions. This of course increases ones exposure to the chemical and increases ones confusion.
It has become so severe over the years, maybe my aging brain is more susceptible to it, that I have taken to not exposing my brain to its noxious fumes at all and hence struggle on bravely to find out how things function without instruction.