From The Conquest of Happiness:

To discover a system for the avoidance of war is a vital need of our civilization; but no such system has a chance while men are so unhappy that mutual extermination seems to them less dreadful than continued endurance of the light of day. To prevent the perpetuation of poverty is necessary if the benefits of machine production are to accrue in any degree to those most in need of them; but what is the use of making everybody rich if the rich themselves are miserable? Education in cruelty and fear is bad, but no other kind can be given by those who are themselves the slaves of these passions.[p. 17]

In this book:

Your frustration results from your habit of comparing reality to an ideal in your head. When the two don't match, you condemn reality. It doesn't occur to you that it might be infinitely easier to simply change your expectations than to bend and twist reality. [p. 93]