This one was a trouble spot for me as a kid:
Manner #3
Do not interrupt grown-ups who are speaking with each other unless there is an emergency. They will notice you and respond when they are finished talking.
I remember it vividly...when I was about 8, I interrupted my mom and aunt for something probably unimportant, after patiently waiting for about 5 minutes for them to stop talking.
When I was scolded for interrupting I said "well if you'd have shut up for 20 seconds I wouldn't have had to interrupt!"
I got in a lot more trouble for that than I did for interrupting...
I think a 3-minute rule should have sufficed in that instance. My mom can talk as much as the next dozen people combined and sometimes needs to be reminded that a conversation and a monologue are two different things.
LOL.... I seem to recall a couple of similar incidents when I was young and stupid. Once with a parent, and once with a teacher.
The once with the teacher; I knew better, but it just slipped out. Regretted it before she laid into me.