Sad news for sure. Been a great 3 years though, and excited for whoever comes next! Definitely hope Clara sticks around.
It's sad when an actor leaves, but what will be even sadder is when the fans in a year from now will say stuff like Matt Smith Sucked as the Doctor. It seems like that's Dr. Who fandom in a nutshell, when a doctor or companion leaves, the negativity comes out.
What do you mean, "when a doctor leaves"?