When Glyph of the Treant was introduced on the Mists of Pandaria beta, I was among those who hurried to glyph it in order to enjoy the form again and subsequently found myself running around Azshara like an idiot, one-shotting the mobs as a tree again. I have difficulty defending this. It literally adds nothing whatsoever to the class. It takes up a valuable glyph slot, gives no combat advantage, and exists only to be enjoyed.
And then I realized -- a lot of the stuff I've liked about Mists has absolutely nothing to do with the druid's combat effectiveness. Something that contributes to tanking, healing, or DPS always has to be balanced with other classes, and a degree of homogenization results because you can't have wildly different mechanics without usually getting wildly different results. Something that doesn't contribute to combat can just exist to be fun and doesn't have to be balanced with similar abilities elsewhere.
What skills, spells, or abilities does your class have that are only for fun? And on a more thoughtful note, would the game benefit from more "dumb stuff"?