I find a similar situation to you and others. I think in my case (and maybe yours) that the stuff you do know and understand your probably good at and better than you think. We all tend to practice what we know right? I find that my lack of confidence and limits on growth to be the gaping holes in some basic theory and other areas I dont really know or dont know I dont know, until im left exposed when playing with friends. Last time my friend (who has always been an amazing player) was surprised at my minor penatatonic playing (I was surprised to learn he doesn't really know much Minor Pent stuff at all) but he KILLED me with his major pentatonic, EVH type stuff. An instant gaping hole, I could barely recognise and certainly didn't know I had until that session. I mean I should have known had I thought about it... but thats the nature of playing at home to the stuff you like (and inevitably know) versus other people and their influences. He loves EVH and associated, I guess, 80's type bands (metallica and so on), Until recently EVH did nothing for me and Metallica still "meh". I Love Led Zep and earlier 70's stuff and Grunge / riff rock so we each have developed a variation in genres and styles. He's still way better than me though (damn it! ) I suspect this is your inward (sub conscious maybe?) fear or brick wall re playing out, the chance of being exposed. Great thread, very interesting.