Why do I not find farting funny? I likewise don't find pooping funny; profoundly satisfying and worthy of much analysis, yes, and the cause of envy of those who possess vastly superior pooping ability, but not humorous in the context of a storyline.
Other bodily-function-related plot contrivances and sight gags I don't find funny:
3. Scratching testicles
4. Getting hit in the crotch
5. Basically anything involves crotches, actually
I also hate public farts. I don't want to have other people's farticles in my nose. They don't belong there, and enough things are taking up residence in my sinuses and they don't need any company. It's OK for Christian to have flatulence in our home as, when you get married, you essentially agree to inhale each others previous day's dinners until death do you stop smelling, but I did NOT sign that contract with anyone else.
Bathrooms have a purpose people, and that purpose is to allow us to catch up on periodicals and relieve our souls, not to financially benefit Hollywood.