During the opening act, the friend on my left tapped me on the shoulder and whispered to me, "Do you see the blond-haired woman in front of us? Doesn't she look like a bobble-head?"
I looked over and, because of the thinness of the woman's neck, the largeness and roundness of her hairstyle, and the particular way she was nodding her head in time to the music, she did indeed look like a life-sized bobble-head doll.
The effect of this knowledge was immediate. First of all, I couldn't look at her, because I would start laughing. Second of all, I became very conscious of my own head movements and tried to keep as still as possible.
After a few minutes, the friend on my right leaned over and whispered to me, "I think that woman on the end looks like a bobble-head doll."
The opening act played some more songs, and the polygamist seated in front of me started talking to one of his wives -- a fairly quiet conversation which didn't bother me, but it appeared to irritate the bobble-head woman. So after a few minutes she leaned over, tapped the polygamist's knee, and gave him a pointedly annoyed look. The polygamist and his wife, suitably chastened, stopped talking. A few minutes later, the wife looked over at the other woman, leaned over, and whispered something in her polygamist husband's ear. He glanced over and started to laugh; then he got himself under control, glanced over again, and started laughing again. Aha, I thought. Bobble-head.