The inverted American “OK” sign is an obscene gesture.
Avoid putting your feet up on a chair, desk or table.
It tends to be considered rude to use a toothpick in public.
It is disgusting if a man spits in the street, but it is more disgusting if a woman does it.
It’s rude to burp not only in a meal but all the time. It’s rude to fart in public.
