I get the same feeling from restoring a tv and seeing a picture come up nice and clear, as when i get a classic car to sputter back to life after decades of sleeping. Theyre not "junk" anymore, they have a purpose again.
I dont know why i love to repair old things. I just do. Its cool, its history, with a bit of help it can be working history again. Plus, what else do i have to do in my spare time BUT play with old junk?