Pessimism, The Key To Happiness?

Roger Scruton defends negative thinking:

In order to see human beings as they are, therefore, and to school oneself in the art of loving them, it is necessary to apply a dose of pessimism to all one’s plans and aspirations. I don’t go along with Schopenhauer’s comprehensive gloom, or with the philosophy of renunciation that he derived from it. I have no doubt that St Paul was right to recommend faith, hope and love (agape) as the virtues which order life to the greater good. But I have no doubt too that hope, detached from faith and untempered by the evidence of history, is a dangerous asset, and one that threatens not only those who embrace it, but all those within range of their illusions.