Explain shafts - is mojo involved?

Since starting golfing, I've become increasingly nerdy about hardware. This is typical for me.

I've recently learned how to reshaft carbon fiber and steel shafts, which has allowed me and son to try out the limited shafts we have here at home.

I've read that shafts can be an amazing magic that transforms your game, but also that that's a crock, and super expensive shafts don't have any magic in them.

What's your experience or expertise in this area?