Comedy is illogic. It is the art of contradictory identification. Its purpose is to allow us to enjoy the undercutting, intellectually or physically, of what we regard as wrong, bad, bizarre, inane, stupid, silly and irrational. When you have decided what is right, good, expected, sensible, serious and rational, you free your mind to assert and recognise its antithesis. Your sense of humour is, in fact, your sense of right and wrong. Humour is your value judgements.
There is an objective sense of humour. This is why people who don't share the same sense of humour often can't help feeling dislike for each other. What a man laughs at, is a reflection of his humour, irrespective of what his consciously held or verbally professed beliefs are. This is also why nearly all of us laugh at some jokes: we live in the same reality, and are almost inevitably going to arrive at some identical identifications regardless of background.
Something is only funny in regard to someone's sense of right and wrong. When someone says "you're not funny" or "you have no sense of humour", they're implicitly stating: "There is something wrong with your value judgements."
In order for comedy to work, it has to be asserted. To assert, means to state as true. Self-assertiveness is the quality of stating onesself as true (dwell on that!). A man can assert through his speech, through body language, bodily functions, noises, and through all forms of art.
The rational man should enjoy the disachievement of non-values, and [comedy] is the means to this joy. It is a reaffirmation of his existence and an end in itself.
This is the core principle underlying comedy. People who reject it are, by the only reason I can foresee, trying to reconcile rational and irrational values together, and thus they must think that laughing at certain goods is possible or that laughing at certain evils is impossible. Comedy gives man the power to detect his irrationalities if he dares to look.
I initially felt unsympathetic towards Rand when I first read that laughing at onesself is "spitting in one's own face". It made logical sense to me, but I felt opposed to it. This is because I had repressed my sense of my right to my own life. All second-handedness begins by deciding not to assert onesself. If you have felt the same way, then perhaps you have been doing the same thing.
I will post more on that last paragraph later under a new topic. For now I will leave you with this: If you think of something that you consider funny, it is vital for your psychological health that you say it.