Minerva: Well, clearly the question is an example of what one might call anti-humor. The majority of jokes involve a clever punchline of some kind, a play on words, so the obvious answer of To get to the other side, which might otherwise have no other comedic value in and of itself, generates a laugh by simply defying the norm of joke telling. However, this particular joke has been so overused as to become trite and cliché. To be perfectly honest, I didn't find it particularly funny the first time I heard it; it's very simplistic, cheap humor, that requires absolutely no knowledge of psychology or quantum physics.
Artemis: Thank you, I couldn't have explained it better myself.
Holly: ...Somebody shoot me. Hey, Butler? I think now would be a good time to have that talk about jokes.
“After all, absolutely no one can help but suspect a criminal, liar, and manipulator of committing crimes, lying, and manipulating. And of course, no one is more aware of that simple fact than Artemis Fowl.”
Opal sets into motion her most diabolical scheme yet, to frame Artemis and turn his closest friends against him. Only this time she has a new calculating partner who knows Artemis better than he knows himself. [An Artemis Fowl fanfiction, set after The Atlantic Complex.] https://www.fanfiction.net/s/8336552/1/Noble-Heart
...Shameless self-advertising, guys! C;
(And if you're really bored: http://axxonu.deviantart.com/gallery/28912232/Artemis-Fowl
AF fanart. ;J)