In relations with others, one should express resentment and anger openly and straightforwardly. If one cannot express them openly and straightforwardly, the only thing to do is forget about them. To harbor grievances in one's heart, awaiting some later opportunity to give vent to them, is to act like a weak and petty man-in truth, it can only be called cowardice. The mind of the superior man is like Heaven. When it is resentful or angry, it thunders forth its indignation. But once having loosed its feelings, it is like a sunny day with a clear sky: within the heart there remains not the trace of a cloud. Such is the beauty of true manliness.

Vol. III. - Yoshida Shoin Zenshu