Tennant’s first episode as the Doctor was a Christmas special and what I love most about it is how caring, and protective Rose is over him. She really doesn’t understand what’s happened yet she just knows that his face has changed right in front of her. So when he wakes up and by his very presence, by his very energy she knows that he’s her doctor. It’s just a very sweet moment, when he’s a little sarcastic and he looks at her and goes “oh that was a bit rude wasn’t it” and she just nods at him and says yeah. It shows that despite his regeneration that their relationship is still very real. I also know that this is entirely an internet theory but I really love the idea of it, that the regeneration of the doctor reveals the relationship with their last companion. Like it was very clear that Eccelston’s who and Rose were very much in love but his appearance was too old for her so when he regenerated he got younger and cuter and they are very clearly very well matched. And the fact that they are best friends in real life really shows through.
This is one of the most heartbreaking seasons on television. David Tennent is such an incredible Doctor and because you were already attached to Rose and the Doctor before Tenant took over, falling in love with them as a couple this season was effortless and beyond easy.
Rose gets trapped in a different world, mirroring the main one in every way except here she doesn’t have the Doctor. It’s one of the most painful endings the audience ever had to experience because we all knew they were in love and now Rose is alone and so is the Doctor. And we already know how lonely the Doctor is, so seeing him lose his love and companion is rough.