yeah some of my favorite players spin out from time to time - if you're really going for it, it's bound to happen. But also sometimes things are unexpected but not 'mistakes'. I remember seeing Joe Satriani play live once ages ago, and it was pretty amazing that he played every song note for note, but pretty quickly got boring as there was no sense of immediacy, or danger - it was a well-rehearsed show, but left me cold - I like to hear someone go for it and see what happens on that particular night at that moment.