On my first day in show business, as a terrified young comedy writer, I found myself sitting in a room with a few comedy legends, trying to rewrite a script.
These men - and they were all men - were the lions of the business. We were working on the biggest hit comedy programme in television at the time, but for most of them it was just another gig. Another very well paid gig.
What they taught me that day, and in the weeks that followed, were the rules of comedy.
(Just to be clear here: when I use the word "taught" in this context, I mean it in the sense of "mocked and humiliated until I learnt.")
There aren't that many rules, really, to comedy. There are just a few: put the funny word at the end of the sentence, make sure the set-up before the punchline is clear enough - that sort of thing.
That's about all I know when it comes to comedy. But if you want to know more about it, a lot more - and prepare yourself, because when I say "a lot more" in this context, I mean it in the sense of an almost 300-page exegesis, thoughtful, sometimes technical, and packed with charts-and-graphs - then you should spring for a book published last month by a friend of mine, Dan O'Shannon, called What Are You Laughing At?
Dan was a couple of grades above me in the ranks back on that day when I started working in the writers' room. But he was then, and still is, one of the most talented writers in the business - and he has a shelf full of Emmy Awards to prove it. But he is also one of the funniest in the business, and that isn't always the same thing.
Dan was a writer for the classic sitcoms Cheers and Frasier and a lot of other shows besides, and now is one of the guiding creative forces behind the hit comedy Modern Family. He knows what he's talking about. But he also takes comedy seriously.
So when Dan sat down to write a book with the subtitle A Comprehensive Guide to the Comedic Event, well, it's the kind of thing that in anyone else's hands - and I'll to be totally honest here, it's the kind of thing that in my hands, especially, because I can be awfully pompous when I'm not paying attention - would without any doubt immediately go horribly, horribly wrong.
But in his hands it goes horribly right, in a way, because he really does fillet a joke like you would a fish, and lay it all out there. If you've got a mind for that sort of thing you'll eat this fish up.
But even if you don't - and I don't - it's a lively and witty book, and he somehow manages to pull off an amazing trick: he has found a way to write about what makes things funny without killing the funny part.
And yet the comedy writers I know have an uneasy relationship to the book. Because a lot of them know Dan, and know how smart he is, and know how right the book must be, they tend to feel the same way as I do: they bought the book out of loyalty to their friend, but they're not about to actually read it.
A lot of comedy writers don't really know what makes a joke work, and we're not really keen to find out.
A lot of us are happy with our superstitious little precepts like "last word is funny" and "fix the set-up" because for most of us, it's not a magic trick that someone can explain, it's magic itself. And we're worried that if we think too hard about it, it might vanish. And if it vanishes, so do the house payments, and the kids' college money and the summer trip to Europe.
We're like tribesmen of old - we don't know how the rain dance works, we just know it's raining. Sometimes not knowing is a lot more reassuring than knowing. I'll stick to the rain dance, thank you.
Rob Long is a writer and producer based in Hollywood
On Twitter: @rbcl