Normally, I'd agree, but then I remember the musical episode from Scrubs and I start laughing all over again. Granted, that was on a sitcom, and one that had goofy side-scenes practically built into the skeleton of the show.
Personally, I like when shows do this kind of thing. It throws a neat "intermission" in between "Crap crap crap we gotta get faster, and take out this villain-of-the-week, because we are running out of time before someone is going to die!" Supernatural does this type of thing once or twice a season, and usually does it really well. Arguably, on a show about slaying monsters and saving the world, there shouldn't be room for an episode where Dean starts to act like a German Shepard, but the premise justified it and seeing him yell angrily at a mailman from a window was pretty damn funny.
