You need to have at least a medium understanding of everything the Doctor has done in his past incarnations to understand how much of a badass the Doctor is. I hear all these people taking about "Tennant vs Smith, who's the best doctor?" when they don't even know the past incarnations and all the ways the Doctor has saved the universe - not just the world, but the UNIVERSE, ALL SPACE AND TIME. One Time Lord. People talk about him being good-looking now, or how awesome and enthusiastic/active/funny/charismatic he is, but they don't understand the /DOCTOR/- he's ended lives and worlds, he sent his own kind into a timevoid - he's torn inside yet he still finds himself saving lives, human or alien, no matter what. He's more than a hero, he's more like a God, in a way.
It's too much to be able to describe in one sitting, especially on fj, but I just needed to put it out there that some people don't really appreciate the Doctor for who he really is.
Im an extreme Doctor Who-ist, and I sometimes find it annoying how many people don't take in the whole person of who the Doctor is... Not about here on FJ, but in life in general..
Also, click on image. Found it earlier online