The fart joke didn't bug me so much. If Kermit tells Fozzie that that's the kind of lowbrow humor that plays in Reno, but not the Muppet Theater, I'll be good with it. Was it just me or did Fozzie's legs appear unusually long in that shot?
The one gag that bugged me was Walter on the electric fence. Just standing and staring at him for too long, not trying to rescue him, just didn't do it for me.
On the other hand, so many things made me smile. The arches, the crowded car ride (with Mahna Mahna--please tell me that's the original show version so least Jim Henson's voice will be heard in this movie!), Bobo's fencing scene, the Bunsen & Beaker at CERN, Miss Piggy actually sounding like herself...lovin' all that!