The performers i really find troublesome are the singer/songwriters who explain the song for 10 or more minutes and then the song goes on and on and on and usually even has a moral to the story. Gag. Seldom is there a spark that fires up the audience when that happens.
In regards to perfect performances versus emotion. I may be prejudiced by the fact that i can never do a perfect performance but. . . When i play the audiences tap their toes, sing along, and look and act happy even if i make a mistake. I contrast that to a guitarist that I saw perform a couple of weeks ago that had amazing chops and the attention of three people in the audience. He was using digital tape loops and all kinds of effects. He was playing with himself. There was no feed back from the audience because they had already left the room even if they were still sitting there. He never made contact with them. Let me be less than perfect but let me have the audience responding and having a good time.