Some people think they are funny, others don't. It's a bodily function that everyone does and a part of life.
Personally I think farts are funny, but there is a time and place for everything.
E.G letting a huge fart rip during one minute silence at a footy stadium with large crowd, is not the time nor the place. Nor a church, funeral, or any other event where respect is required. Cropdusting the aisles of a shopping centre is generally a no no as well.
Lets not forget the farts mortal enemy - the shart. Farts = funny for some, Sharts = funny for everyone except the person who has just s##t themselves.