In rock and metal, usually the best guitar solos were improvised on the spot, and it's practically impossible to recapture that moment the same way again.
In a funny bit of serendipity, I was talking with somebody the other day about things that make you feel old, and this person told me his young son saw a pay phone in a movie and asked, "What's that?"
I can attest it's probably easier to get the Pope on the phone than to get an interview with Martin Scorsese, and we all know that attempting to get an articulate answer out of DeNiro in an interview is akin to trying to part the Red Sea.