The Time Lords are an immensely civilised race. We can control our own environment - we can live forever, barring accidents and we have the secret of space/time travel.. [But] we hardly ever use our great powers! We are simply to observe and gather knowledge
Zoe: And that wasn’t enough for you?
The Doctor: No. Of course not. With a whole galaxy to explore; millions of planets, eons of time, countless civilisations to meet..
Jamie: Well why do they object to you doing all that?
The Doctor: Well…it is a fact, Jamie, that I do tend to get involved with things
Jamie: Aye, you can say that again. Whenever there’s any trouble, he’s in it right up to his neck.