avoiding inadvertent insults

Some nonverbal signals

In the US, raising one finger means “Give me a minute”. It can be very helpful if you’re processing slowly or need some time to find works.

However, shaking a finger means “You’re doing something I don’t like, and I’m expressing contempt by treating you like a naughty child”.

So, it’s a signal that doesn’t work well if you can’t easily tell the difference between raising your finger and shaking your finger.