(It's possible that this person was careful never to show a feeling of misery around others, as in the story of a rabbi who said he suppressed his crying when his mother was around and only let himself go -- as a baby yet -- when she would not hear).
We see multiple instances of great people having difficulties and not remaining calm. There were points at which Moshe lost patience with the complaints and rebellions of the people he had to lead. Rachel had an altercation with Yaakov, who responded fairly harshly. Leah expressed her own resentment to Rachel when her sister asked for the flowers that Reuven gathered. Yaakov gave Lavan a piece of his mind that showed he did feel resentful for all the difficulties he endured in his father-in-law's employ. The fact that the Torah reveals all this to us shows that even they had moments when they got overwhelmed. That does not diminish from their greatness; on the contrary, it shows that even those who feel that way can can achieve the pinnacle of spiritual heights. I find that more inspiring than hearing about someone who never, ever cried out because I simply can't relate to it.
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