Eve, I think a little of that was "acting." The more surprised and shocked they looked, the better it would be to the audiences. It's like the American Idol try outs--if you watch long and carefully enough, you can pick up signs that they know who is truly terrible and who has some talent.
Mr. Texana and I have talked about this issue ad nauseum--that back in the day (pick any day) a musician was judged on talent alone. Now they have to look good as well as have talent, and the overall quality of performance has gone down.
I would love for Susan Boyle to be the start of turning back that trend.