I used to work for a company that manufactured flat pack furniture and it was amazing what mistakes people made because they hadn't read the instructions. They even sent us photos of their bodged work telling us that our product was rubbish. As it was clearly explained in the instructions, they had no leg to stand on and we always charged for replacements.
My DH always buys expensive equipment because the salesperson tells him all the advantages it has and all the useful functions available. But once it is installed, he never bothers to read the instructions, and never uses all the bells and whistles. E.g., he just switches the TV on and changes channels if necessary. If I call him to dinner whilst he is watching something, he has no idea how to record the rest of the programme to watch it when he gets back to it.
I read all the instructions and know how to do all the snazzy tricks, but I never watch the TV anyway.
With other things, too, particularly electronic ones, I read all the instructions, but I am also usually able to figure out intuitively how to work them. Which is helpful when there are mistakes in the instructions. He is a bit of a luddite, really.