GuyCC
Yeah, to some of the earlier comments, we don't know that much about the Doctor, as he never talks about his past. He never states that much about any family, other than a few hints to show that he has/had one, and they still tease about what his name really is all the time.
But yeah, the first version of the Doctor was not all that particularly nice to people he met, or even his own companions. He mellowed out towards the end.
The Sixth Doctor tried to kill his companion upon regeneration.
The Seventh Doctor started as whimsical, but became manipulative and calculation, not even sharing his motives with his companions.
Donna even noted the Tenth Doctor needed someone to essentially keep him in line.
He's not always a nice fellow by any means of the word, not even his current form.
Oh, and Kingpin, the TARDIS console has six sides (loved how they explained the function of it in the last episode).
Yea. They have hinted in key episodes about his past and his role in the Time War. And why he is called Doctor instead of a regular name. From what I gathered, its not a happy story which makes sense if you take the first Doctor(as has been told above) into account. What ever happened made him a bitter and hateful Doctor. Also, in the Series 4 finale it looked like that 3 eyed Daylek hybrid fellow hit a chord with the Doctor when he was talking about him with Donna and the others there in front of him. He didn't look one bit like the regular happy-go-lucky and whimsical Doctor.
Yea. He did say he needed Donna to keep him in line. I think its cuz he was never really over leaving Rose in the alternate dimension and needed somebody from making him loose his mind from the grief.
It also makes sense why the Tardis needs that many pilots cuz it beats one pilot, like the Doctor, rushing around and trying to find the right control, lever, button, knob or handle to use.
I really need to see the classic Doctors. But alas I might not have the time.