I don't know who decided it, but it's a rule: farts are funny.
Instance one: In a second-grade music class, the teacher says, "Now we're going to look at the instruments. Everyone needs to be absolutely quiet and listen or you might not get to play today." As the teacher begins to move, a little girl about the size of a thimble (but cuter) lets one rip that, had it emerged from a 200-pound teamster, would have been heroic. Coming from that tiny thing, it was almost miraculous. Torn between shock and awe, the teacher froze as the class erupted in laughter. Worse, the teacher, who is, after all, only human, could not help but laugh. Order was restored eventually, but it was a delicate balance: one small puff of air would have sent their fragile house of discipline crashing to the ground.
Why are these completely natural bodily emissions funny? And why are they funny to EVERYONE? I don't mean every person, but I have yet to meet one "type" of person who consistently does not find farts funny.
Example: Princess was about four months old the first time she deliberately farted against the bottom of the bathtub and giggled. Precocious? Gifted? Genius? Certainly.
Example 2: The other day, Dexy was in the bath. He was splashing happily while I got the towels ready and I heard, "Mommy! Come here!" I went to the side of the tub where he was standing, a look of intense concentration on his face. He held out a hand for mine. As he clasped my hand, he farted. He laughed, still holding my hand, for about two full minutes, became serious, looked me in the eye, and said, "I poot." Then he did it again.
I have heard that there are some cultures in which farting is completely commonplace. No one notices them at all, they are like random coughs. So obviously, it's our social taboo on the whole subject of digestion and excretion that makes farts (and fart jokes, and poo jokes, and toilet humor in general) funny. The forbidden is always a good source of comedy.
Of course, it can go too far, and I think we can all agree that when it does, it stops being funny and is just gross. What we can't agree on is where that line is; to one person, the bathroom scene in "Dumb and Dumber" is completely disgusting and absolutely devoid of any humor at all, whereas another gets the giggles just thinking about it as she types her blog.
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