The Ninth Doctor clearly suffered through Post Traumatic Stress Disorder and was a man frightened of himself and what he could do, who still tried his best to carry on because he couldn’t think of anything else to do with himself. And then he met a girl. A girl who was willing to take some of the weight, who believed he was absolutely everything in the universe, who knew he was worth it when he had all but given up on himself. The only problem was, he was a little old to be her boyfriend.
When all hope seemed lost, that girl came back to him and saved him. And that was the moment, the place where the Doctor came back, too, and realized that he was still pleased to be that man even after all he had done. More importantly, he realized that he loved that girl. And as he regenerated, he was thinking of that love and thinking of renewal, and he probably thought it would be fantastic if he could just be perfect for her. To be what Rose needed him to be. Time to be younger and brighter, cocky but cool, more physical and even more mouthy.
And no one would ever tell him that he was too old to be Rose’s boyfriend again.
From “Not Some New Man: The Hidden Pattern Behind the Doctor’s Regenerations”
Awesome article for Dr Who Fans. Definitely gives a lot of insight into the inter-workings of all of the doctors! ~S