Manners are much underrated. In fact they "oil the wheels" of everyday behaviour and make it possible for people to exchange ideas etc. in a cooperative environment, and allow for dissent.

Personally I would be happy to see the end of institutionalised religions of all sorts. Many religious customs have grown to include condoning extremely bad manners, and sometimes have encouraged dodgy ethics too.

The Golden Rule, as I have said before, covers most situations. That is--do as you would be done by.