With Manners Manners are constantly changing from one century or one generation to the next. For example, a handshake originally was meant to show that men were not carrying a sword or dagger in their hands. Men still tip their hats because once knights in armor lifted the visors of their helmets to show their faces. And it wasn't too many years ago that a man almost always got up in a crowded bus and gave his seat to a woman. Nevertheless, certain manners do survive from one decade to the next, and this is because manners make life easier for everybody.
Custom is the habit of doing certain things like shaking hands and tipping hats mentioned above.
Consideration is the most important idea behind all good manners. Almost always, being considerate is being well-mannered. Consideration is simply thinking about the way the other person feels. Being rude to someone is bad manners, not because a book says so, but because it causes hurt feelings. Nearly all good manners have in element of common sense.