In “Ingersollia”, the 1882 compilation of thoughts from lectures, and conversations of Robert Ingersoll, the lawyer and agnostic thinker, we read:
A cross man I hate above all things. What right has he to murder the sushine of the day? What right has he to assassinate the joy of life? When you go home you ought to feel the light there is in the house; if it is in the night it will burst out of the doors and illuminate the darkness.
Christophe Andre, the psychiatrist, confesses (“In Search of Wisdom” ) that he is “a depressive type who can….reason in a twisted way in order to justify his way of seeing the world.” He goes on to tell us about his daughter who “for two years….had been in intensive classes preparing for university entrance exams”. She led “a hard life” with long hours of commuting as well. Christophe writes: “And every morning I got up with her, made her orange juice, her coffee, her sandwich, thinking it was important for me to be there. She was practically joyous and had a smile on her face, even in the cold and dark winter, even at exam time. Some mornings she would ask me how I was feeling, and sometimes I wasn’t feeling that well but I didn’t want her to see it, so I’d say, “Oh, I’m okay, doing okay.” And she would scold me, saying, “Okay? Your ‘okay’ doesn’t sound very convincing.” Little by little I got the point. And one day it became clear enough for me to articulate: No matter what happens, you find every reason to be happy in the morning.”
In a letter (“The Letters of Robert Browning and Elizabeth Barrett — Volume 1, 1845-1846”) written on 5th March 1845, some time before she met and married Robert Browning, the poet Elizabeth Barrett (who suffered from illnesses and chronic pain from an early age) tells him that she has “after a course of bitter mental discipline and long bodily seclusion” learned “the wisdom of cheerfulness.”
In his talks on Bhakti Yoga (“The Complete Works of Swami Vivekananda”), we hear Swami Vivekananda tell us that the person who aspires to the highest realization, “must be cheerful.” Swamiji explains why. “It is the cheerful mind that is persevering. It is the strong mind that hews its way through a thousand difficulties.”