Anger is stupid, and stupidity will kill you more surely than your opponent's blade.

A stupid ruler is much more of a problem than an insane one.

I belong to a stupid nation that kill and murder their own people for language and religion, then they call it foreigners interference.

It's stupid not to act stupid sometimes.

I'm allergic to stupidity.

If it is stupid but it works, it isn't stupid.
(a Shin'a'in saying)