Comment by jwr

Music engages your creative hemisphere, thus hampering your creative thinking capabilities.

For me this wasn't a problem when configuring routers, but I found that if I listened to music, I could spend an hour programming a solution to a problem that could have been sidestepped entirely.

I read some articles about that, but don't have a reference handy. In any case, once I noticed the effects it has on me, I am being extra careful.