Our 8 year old (boy) is a rather socially vocal about things that interest him, or anything that grabs his mind, what I mean by that is that he will (at length) talk to anyone around him about his current interest subject (right now it's fishing) or his life (and our family) history, regardless of whether they've shown any interest or not. He will often random start conversations with people who have started an unrelated passing conversation with us (cashiers, random people on the bus, family members e.t.c) about these things, when it's clear (to us) that they are completely lost about what he's talking about.
We've tried explaining to him on numerous occasions that not everyone enjoys being subject to an half hour long conversation about fishing or Minecraft or Egypt or whatever the flavour of the period is, but it seems to not be getting through. It's gotten to the point where a lot of his school peers have started actively ignoring him when he approaches them because they're just not interested.
Obviously we don't want to squash his enthusiasm for these subjects, or any subject, to stop him exploring his interests, but we feel that he's going to have trouble finding friends if he doesn't recognise other peoples interest (or lack-of).
How have other people handled this (or similar) situations?
Personally I feel that some of the cause comes from him trying to establish himself as a clever child, as a lot of the children in his class seem to have a rather high opinion of themselves, but he is a clever child - just when he exerts himself. He also seems to be suffering from some confidence issues - he refuses to apply himself to things which he can do, he just doesn't think he's able to (but I'm thinking this is normal behaviour in children?)