Parents of elementary school children love to see them perform on stage, regardless of how horrendous those performances are. Not only can they do nothing wrong, but if the performance is flawed, it only seems to make it cuter and more endearing to the parents observing. Aware of this fact, schools arrange such performances, knowing that it's sure to garner bonus points for the school. Skill levels aside, student performances are scheduled during the year, especially at Xmas time.
As an elementary student, I had a music teacher I'll call Mrs. Grey (not her real name). Now Mrs. Grey was an older teacher, and had many strengths as a music teacher. Performance in a class choir before an audience at Christmas time was mandatory, and for the occasion Mrs. Grey chose to wear a sleeveless top. As she vigorously directed the children's choir, great bags of arm fat and loose skin bounced up and down with each pumping motion of her arms, and there were many of them. It was a poor fashion choice for a woman in her occupation.
As a student, I was riveted yet horrified by the spectacle of these jiggling bags of arm fat bouncing around under Mrs. Grey's directing arms, yet I could not look away! It was kind of an approach/avoidance conflict similar to that which a person might experience when looking at an image of a grisly mummy; you are repelled, yet unable to look away as your mind records each detail.
And so it is that years later, I have vivid mental images of choir director bouncing arm fat burned into my brain when thought enters of youth choir performances. That and the fact that my school had an actual mummy displayed likely added to my tendencies to focus on the offbeat, strange, and horrific in life...