There's lots of reasons I'd love to be a dog, the biggest one being they don't have to work. Most of them don't, anyway. I'm not sure I could be a drug sniffing dog, with my penchant for getting sinus infections. "Ah, I'm not sure if there's drugs in that bag, boss, but there's definitely some Claritin."
The thing I would miss the most about being human, if I were a dog, is that I couldn't read a magazine while pooping. I learn so much during this valuable reading time. Clearly the position that dogs must assume to do their business doesn't allow for holding a magazine, or turning pages.
Oh, and I couldn't read. That's a stumbling block too.