Well, funny story there Geordie, I saw a documentary on hikikomori when I was younger and realised this is what I had become, I think I had just reached a point in my life where trying to associate with people was less rewarding and more painful than the fantasy world I could create for myself.
So I think it is most likely half and half, half of it is realising you don't want to die but you don't want to live, so maybe shutting yourself away is easier and the other half is knowing that because people only like what they can explain, dealing with you is too hard for most people so they either mistreat you or ignore you... at least I found it to be 50/50.
I hope you are having no feelings that this is a good option for you, it is not, it never is, come to AC instead.
Hope that helps ; ]