INT. TALKING HEAD.
NEWSREADER:
It has been established conclusively today by a panel of experts from The British Sitcom Forum that both everything and nothing are funny, er is funny. If you think it's funny, it's funny. Nobody can tell you it's not funny because funny is subjective. Ergo they can't tell you it's funny either.
Also, if you think it's not funny then it's not funny. So your joke is probably funny unless it isn't. Although some people will swear blind that it's not funny, whilst laughing at it. It has also been suggested that others will tell you it's rip-roaringly funny with the straightest of faces when it plainly sucks. So there you have it.
Your joke is funny, maybe, unless it's not. Your best bet is to have two heads. Use one head to tell yourself a joke and then use the other head to rate it funny or not and you'll probably be right. Or left. Of course, they'll call you two-faced to your face (either or both) or behind your back, or both. But you can tell them that "Funny Stuff" is what Producers pay money for except that sometimes even that stuff is not funny, BUT that's the only time you can really laugh.