Simon James Holliday Gray (21 October 1936 – 7 August 2008) was an English playwright and memoirist who also had a career as a university lecturer in English literature at Queen Mary, University of London, for 20 years. While teaching at Queen Mary, Gray began his writing career as a novelist in 1963 and, during the next 45 years, in addition to five published novels, wrote 40 original stage plays, screenplays, and screen adaptations of his own and others' works for stage, film, and television and became well known for the self-deprecating wit characteristic of several volumes of memoirs or diaries.
You may find more from Simon Gray on Wikiquote
This is what the world honors: wealth, eminence, long life, a good name. This is what the world finds happiness in: a life of ease, rich food, fine clothes, beautiful sights, sweet sounds. People who can't get these things fret a great deal and are afraid, wear themselves out rushing around on business, spend night and day scheming and scrutinizing. Man lives his life in company with worry, and if he lives a long time, then he has spent that much time worrying. This is a callous way to treat the body.
Happiness is always a byproduct. It is probably a matter of temperament, and for anything I know it may be glandular. But it is not something that can be demanded from life, and if you are not happy, you had better stop worrying about it and see what treasures you can pluck from your own brand of unhappiness.