Manners

What has happened to this thing called Manners or Good ediquette??  When a person gets an invitation, they should RSVP.  Respond Very Promply (I think)    Another thing that is bugging me is why do people think they dont have to do anything and that everyone owes them.  They are very self minded.  They dont show happiness for anyone else but when good things happen to them they expect everyone to just flock and celebrate with them.  They also dont say thank you for gifts they are given.