para-phrase this passage: When a person with a sense of humour laughs in the face of his own failure, he is showing that his perspective transcends the particular situation he's in, and that he does not have an egocentric, overly precious view of his own endeavours. This is not to say he lacks self-esteem-quite the contrary. It is because he feels good about himself at a fundamental level that this or that setback is not threatening to him. The person without self-esteem, on the other hand, who is unsure of his own worth, tends to invest his whole sense of himself in each of his projects. Whether he fails or succeeds, he is not likely to see things in an objective way; because his ego rides on each of any success personal triumph. He simply cannot laugh at himself, whatever happens. So having a sense of humour about oneself is psychologically healthy.