This is a really interesting thread.
I don't present well at an audition (long standing anxiety issues) but am a real asset on stage. On the other hand I am great fun to be around in the first 12 months of any band, then the d|ck side of my nature starts to come out and I'll be great friends with one other member of the band, ambivalent about one other and detest the other one.
I will always be first to the venue, learn everything, carry spares of everything; I'm creative and sensitive to the needs of the song, but simultaneously ridiculously over sensitive to criticism - real or imagined.
You wouldn't know any of this from an audition. Difficult isn't it?