It is not the strength, but the duration of high feelings that makes great men.
Beyond Good & Evil paragraph 72
Lofty Moods. — It seems to me that most men do not believe in lofty moods, unless it be for the moment, or at the most for a quarter of an hour, — except the few who know by experience a longer duration of high feeling. But to be absolutely a man with a single lofty feeling, the incarnation of a single lofty mood — that has hitherto been only a dream and an enchanting possibility: history does not yet give us any trustworthy example of it. Nevertheless one might also some day produce such men — when a multitude of favorable conditions have been created and established, which at present even the happiest chance is unable to throw together. Perhaps that very state which has hitherto entered into our soul as an exception, felt with horror now and then, may be the usual condition of those future souls: a continuous movement between high and low, and the feeling of high and low, a constant state of mounting as on steps, and at the same time reposing as on clouds.
Gay Science paragraph 288
Having much joy. – He who has much joy in his life must be a good man: but he is perhaps not the cleverest, even though he has attained precisely that which the cleverest man strives after with all his cleverness.
Human, All Too Human, part 2, paragraph 48