whether you do or do not open a gift in the presence of the give; whether you put on your coat before or after you leave the host's house; whether you eat as quietly or as noisily as possible; whether you carry on a conversation during a meal - these and a thousand other customs vary form country to country. The idea behind all codes of be-haviour is to make life flow smoothly. No one way of behaviour is right or wrong and no one way can be called "good" or "bad" manners except as a society defines it so.