from Book I of Meditations. The passage came back to mind. Age is no reference point in this matter. We find this trait in children as well as in adults.
If this is not learnable, let us at least recognize it in others, and admire it.
"Maximus was my model for self-control, fixity of purpose, and cheerfulness under ill-health or other misfortunes. His character was an admirable combination of dignity and charm, and all the duties of his station were performed quietly and without fuss. He gave everyone the conviction that he spoke as he believed, and acted as he judged right."
(Meditations, Book I.15)