Wheel
of Time RPG
A very proud nation, the Cairhienin see plot against them and everyone else in anything someone says if they are not careful and, equally, the Cairhienin themselves watch what they say in case they give something away they did not mean to.
This is called Daes Dae'mar, or 'The Game of Houses', and it is said the people of this land can play it in their sleep.
These people also value order and social class, the highborn stay that way, and the lowborn are discouraged from seeking higher station - and marriages are organized thusly.
However, this is not strict and, especially on the Feast of Lights, all reserve is abandoned and the class structure visibly collapses - though this only lasts for two days, and after that time nothing which happened on the holiday is spoken of again.