It's the school of hard knocks and mis-spent youth...there's a secret handshake and everything.
Once in a while I put on an AEG Workshop where I take a couple of guys through working on AEGs, what's what and give them the opportunity to work on stuff with minimal risk. It's about 14-20 hours worth of material.
So far the guys have come out with the knowledge and confidence to work on their own rifles. I think some work on others stuff. A few have decided that they're glad to know what's in one...but definitely have decided that they never want to touch it themselves.
Fun times...I always try to bring out some interesting toys to fiddle with.