It depends on what's being fixed. As a kid I watched the TV repair man do his thing and he was kind enough to give me a guided tour around the innards of the TV set. I've also sat and watched a plumber turn a collection of water and gas pipes in one combination to a collection of pipes in another using nothing more than elbow joints and experience, THAT was fun to watch. My father was a plasterer and even now I can stand there and watch someone who has the knack chase a bead of water around the wall until the surface is dead flat.
Now, what IS annoying are the people who constantly want to know 'what's that'? or 'what does that do'? as their fingertip gets close to the 1100V anode cap on a power amplifier. As for the 'why didn't you do that, it's much better' crowd, they get shown the door, the secret is to watch an expert at their trade and listen.