Interesting you mention that about bluegrass because that is something that has never set too well with me about bluegrass. They used to play these old old bluegrass songs with gorey details in them at Old Alabama Town. They don't discuss the lyrics or anything. They just play them and sing them and move on to another song. It's all like a secret society seems to me.
Course I haven't been able to go for a couple years now. I teach my kindergarten class slap dab in the middle of the time I used to go play with the mandolin and guitar pickers. Sometimes there was a banjo and an acoustic base even. Lots of guitars. One guy has one that almost looks like Willie Nelson's guitar with an enlarged hole where his fingers have worn the wood down. He's a neat guy. Lot's of them pick VERY very well and one in particular looks like his fingers are popping like popcorn kernals.