I love your first line!

I left a church because the choir director always showed up half an hour late for the one hour pre-service rehearsal, then spent about half the remaining time bitching about her day job.

There’s a community choir I’m part of where the director periodically sends out an email imploring everyone to be on time because we have a performance coming up or whatever reason. I tell him if you would start the rehearsal on time — there’s a few of us who always show up on time — the rest would get the message after being embarrassed a few times then it would gradually stop being an issue. His problem is that he has family in the group and they’re some of the worst offenders. IMHO if they quit in a huff the choir would be better for it. But then he’d be stuck with a s ***ton of family drama.