Modern "emotive" drama requires its characters to behave in quite specific ways if the audience is going to gush properly, and a professional writer will bravely dispense with logical storytelling and/or consistent characterisation in order to get the full effect. Here we see a few examples of how the true pro handles things, and how the amateur (or even fan-fic-level) writer would be needlessly weighed down by notions of common sense or credible behaviour...
Situation: The TARDIS has fallen down a big hole on a newly-discovered planet, and the leader of the expedition has made it clear that they don't have the resources to recover it.
The Proper Version: "The TARDIS... is gone. We're trapped in this place and time forever. Oh, Rose... Rose, I'm so sorry." (Characters begin sobbing. Cue weepy Murray Gold music.)
The Amateur Version: "Right. First thing we do, we get a lift back to the nearest human colony-world. I've got technical skills about eighty-kerjillion years ahead of anyone else in this era, so we shouldn't have any trouble scraping together a few million credits that way... hold on, what am I saying? If the sonic screwdriver can defraud Earth's banking system even in the year 200,000, then in this century I can probably just get the money out of a cash machine. Then we fund our own return expedition to this planet, and hire a drilling team to dig out the TARDIS. Should take, ooh, a couple of months at most?" "Yeah, whatever. I could do with a break anyway."
Situation: The Doctor encounters a mysterious woman who treats him as an old, even intimate, acquaintance.
The Proper Version: "Who are you? How do you know who I am? Why do you keep acting as if we're friends?!? AARRRRRGHHH!" (Cue forty-five minutes of angst and friction, in line with the standards of romantic comedy / action-movie Unresolved Sexual Tension.)
The Amateur Version: "Who are you? How do you know who I am...? Oh, of course! I'm a time-traveller, we must know each other in the future. Surprising this doesn't happen more often, really. No, it's fine, you don't need to prove anything: believing in the decency of strangers is what I've been doing for the last six-hundred years or so, I don't see why I should arbitrarily start being all anxious and paranoid now. Right, enough of the pleasantries, let's put our heads together and work out how to get everyone here to safety."
Situation: Meat-puppet doppelgangers have become self-aware.
The Proper Version: "But... all those memories. Of when I was a little girl. They're real! They must be real!" (Cue weepy Murray Gold music. Sobbing intercut with shots of a speechless Rory, underlining the horror of the fact that he fancies her.)
The Amateur Version: "But... all those memories. Of when I was a little girl. They're real! They must be real! Oh, wait... they are real, aren't they? I mean, when you think about it, every atom in the human body gets lost and replaced within about a decade. So one way or another, we're all copies of ourselves. The important thing is that at least one of me is alive, yeah? Wow. Had a wobbly five minutes there. But, y'know, I come from a civilisation that can wear artifical bodies like T-shirts. It's not like we don't have the cultural apparatus to deal with this sort of thing. God, you should see what we do with the Flesh when we're off-shift, it's just sick. Oh, like we're not going to think about that as soon as we're shown how to use the machinery? And just look what I can do with my neck now! Result. Listen, on that subject... I know you've got a girlfriend and everything, but this whole incident is teaching us to reconsider the boundaries between self and other. So I was thinking..."
Situation: Due to some unimaginable flux in the timeline, Amy is simultaneously pregnant and not pregnant.
The Proper Version: Anxious, obsessive glances at the scanner by the Doctor... who remains silent, but ever-alert to the forces which may even now be enveloping the TARDIS and its crew.
The Amateur Version: "Amy, you know what you said about a baby with a time-head? Er, sorry. It might be true. I wasn't sure if I should tell you, but it is your body, and... well, if we're going to retain any pretence that you're an independent human being or that I have an ethical code of some description, then you've got a right to know. I kept looking at pictures of your womb, and it was getting stalkery. Besides, if I kept quiet about it, it'd obviously just go tits-up in the end." "Oh. Right. Well, um... I've sort of seen you die." "Really?" "Yeah. That horrible woman with the gun fixation? She burned your body and everything." "Ah! Well, we should probably investigate both of those things, then. They're almost certainly connected. Phew! Thank goodness we compared notes, rather than being icily mysterious for no morally or logically defensible reason."
(Update 28/05/11: Yeah... all right, that's a fairly logical reason. But it's still really quite unpleasant. You see? I told you I could never do this.)