If I regarded my life from the point of view of the pessimist, I should be undone. I should seek in vain for the light that does not visit my eyes and the music that does not ring in my ears. I should beg night and day and never be satisfied. I should sit apart in awful solitude, a prey to fear and despair. But since I consider it a duty to myself and to others to be happy, I escape a misery worse than any physical deprivation.
~ Helen Keller.