David Tennant is insufferable. It seems that all he has to do is show up in something and Brits go arse over teakettle about how amazing it is. He could read the ingredients on the back of a can of beets and the crowd would go wild. He seems to have never said no to a role in his life, either. An extensive career in mediocre television movies, comic book pap and cartoon animal voices. There's not a bar too…