It is a bad manner to sit on the floor, on the ground, on the stairs.

It is forbidden to walk and sit on the grass in many public places, especially where flowers grow.

It is considered bad manners to talk loudly, to talk waving hands, etc.

People in USSR were taught not to talk in public transport and not to act attracting others attention. A person who is loud and noticeable may be met with hostility, especially in small towns.