You generally know either way, and in my experience it's foolish you go against your gut instincts on these things, they always prove to be correct in the end. I remember an audition where the band were really tight and I was flattered to get the gig. However even driving away from the audition, before I knew it had been successful, I knew that more than 30-minutes in a room with the singer was not going to work for me, he was a winey low talent tool with delusions of grandeur and only an average voice, and he did that thing where he looks at you occasionally just to let you know you did something he didn't like. Anyway, I was so right π