Experi-Mental Evidence
Has something ever struck you as insanely funny, but you didn't know why (no matter how long you thought about it) and it never struck you as funny again? That's because the Straight Lines and Gag Lines don't have to manifest as things that our best theories consider ``funny.'' Sure, our humor theories work pretty well for most cases that are observable (much as Newtonian mechanics does), but the underlying partickle metaphysics clearly shows that Straight Lines and Gag Lines can show up in any form whatsoever, and their annihilation will create Humor (which is detected as laughter).
      For example, the words ``fat lip'' could be the matching Gag Line for the Straight Line that manifests as sitting in your Mom's living room watching VH1 on a particular date at a particular time. The two annihilate and you start laughing, but you don't know why (what's worse, it's a particularly big reaction and you wind up laughing for half an hour).
      This is a common phenomenon, which is why no one ever thinks it unusual that they've been laughing for no reason at all. If the recipient of the blessing (for it is such, Hail Eris) thinks about it at all, he usually dismisses it hurriedly as being caused by sleep deprivation or low blood sugar (that's Greyface, trying to turn you away from the tickles of Eris).