Full Idea
Those who do not get angry at things that ought to make them angry are considered to be foolish.
Gist of Idea
It is foolish not to be angry when it is appropriate
Source
Aristotle (Nicomachean Ethics [c.334 BCE], 1126a05)
Book Reference
Aristotle: 'Ethics (Nicomachean)', ed/tr. ThomsonJ A K/TredennickH [Penguin 1976], p.161
A Reaction
This remark most clearly shows that Nietzsche did not understand Aristotle, as he seemed to think that Aristotle was recommending bland restraint. Aristotle loves reason, but that does not mean that he admires boring tedium.