The most important nonmusical skill in an ensemble is empathy.
Yes, empathy is a skill. We get better at it by practicing it. And we get less empathetic when we practice selfishness.
Empathy in choir means listening to what’s happening beyond your voice.
Empathy in choir means respecting that others get things faster or slower than you.
Empathy in choir means adjusting your own behavior to better meet the needs of the whole group.
Empathy in choir means trusting those around you to do what’s right, and making generous assumptions when they make mistakes.
Empathy in choir means treating others like they are part of you.
Come to think of it, this is the most important skill for being in society, too.