Sure, it's called "manners", or "social behaviour". Of course, as time goes on, many informal social rules have been made into law, because someone always figur

Sure, it's called "manners", or "social behaviour". Of course, as time goes on, many informal social rules have been made into law, because someone always figures he can live with the disapproving looks. As just one example: If you've agreed to meet with a friend and they don't show, without notice, you'll probably inform them that they are in violation of your unwritten agreement. (I'm not actually in favour of this line of argument, but I believe it's pretty obvious that unwritten social norms exist, and often serve a purpose)