Spoilers for the first two episodes
It might have been when the Doctor was wrestling with the mannequin arm. Cheese-ridden the show may be. But by golly, the two leads are really putting their hearts into it, and Chris Eccleston is just flinging himself into the role, literally and figuratively.
It also might have been when Rose and the Doctor started talking in rapid-fire overlapping Hawkesian dialogue (I waited for the rest of the two eps for them to do that again, but they haven't yet. Aw, nuts. I hope they will that again later because it's adorable.)
Whatever it was, it took like twenty minutes in before I understood why people have been telling me and telling me and telling me to watch this show.
The show is fairly well-written. The special effects range from godawful cheap to oooh, pretty. The show always seems to be very good at walking the tightrope of being wacked-out funny, and then turning on a dime to an unexpected moment of pathos. And then we're right back to fantastic and cheese and funny again.
Rose & The Doctor--um. Yeah. There's enough sexual subtext that the possibility of their romance is out there, but I'll be equally fascinated if it's just their developing partnership and friendship. Because right now there's only the wee start of a partnership and a friendship, and seeing this from the perspective of the beginning, Rose has a crush on him (even though he is such an infuriating man) and I think he kind of thinks she's pretty and sweet but, y'know, very young and doesn't think of her like that and doesn't think that much about her. Except when he remembers that he likes her and having her around and would be sad if anything bad happened to her.
I loved how Rose only smiled big, happy, yeah-I'm-alive smiles when she was running with the Doctor. It's like she's been asleep her whole life and for the first time realizing she's been asleep. He's the last of his kind, and she's bored. So he's lonely and needs her to keep him from being lonely, and she needs a rush. We're not at friendship yet, but the way shows like this work, it's going to be fantastic watching them start to care about each other as people. She's clearly in the sidekick role here--her function is to be in danger so the Doctor can save her, and remind the audience that he does have emotional bonds, he just puts them away in a dark pocket most of the time. The lightness of their relationship now is making me look forward to seeing their friendship really tested later on.
In ep 2, the bit where he tells the tree lady that he's got nothing left so it's a relief to him when there's a crisis and he has something to think about and do (I'm paraphrasing), that was lovely. Eccleston is fabulous in this. He's manic and remote and funny and enigmatic all at the same time.
Piper's performance--well, so far she's merely funny and cute, but since the show is funny, she's doing a great job. Oddly, she's the straight-man of the comedy team, even though she's the funny one, there to make quips and be spunky. While the Doctor is a tragic figure even though he's the source of a lot of the funny.