What is bad dialogue?

I just finished watching the first season of "Jessica Jones", and I mostly kept going to get a full picture, not because it was an especially joyous ride, so you maybe shouldn't follow in my footsteps here. What really egged me about the show, beside some other points of course, was the baffingly bad dialogue. I wanted to share an example of that with you and explain why it is so bad and try to get a bit more into the question when dialogue is to be considered bad. If you want to watch "Jessica Jones" spoilerfree, you'll have to stop reading here, but what I tell you about the plot here is really very light on spoilers, so you might just go ahead anyway.

Without further ado, let's get into it. The situation is as follows: Luke Cage has been knocked out and is now cared for by a ridiculously selfless nurse, Claire, in Jessica's apartment. Her also ridiculously selfless neighbor, Malcolm, comes in (because who doesn't do that all the time), and the following dialogue develops, running roughly two minutes. 

Malcolm: Who are you?
Claire: Who are you?
Malcolm: Neighbor.
Claire: Nurse.
Malcolm: Is Jessica hurt?
Claire: She's allright, as far as I know.
Malcolm: Where is she?
Claire: [sighs]
Malcolm: Jess? [frantically searches around. Sees unconscious Luke Cage.] Oh goddamn.
Claire: You know him?
Malcolm: Yeah Luke. What happened to him?
Claire: I don't know. Not sure I want to.
Malcolm: So, are...you some kind of special nurse?
Claire: "Special"? As in...? [exasperated silence] No, I'm not special. I just keep running into special.
Malcolm: Ah, you and me both. Is it a good thing?
Claire: [sighs] Can't change what we know.
Malcolm: [chuckles] Yeah, I miss ignorance too.

Claire, the nurse. Noticed she's wearing Nurse's clothing?

Let's pause here for a second or two. Nevermind that Malcolm still doesn't know what Jessica is up to or whether she's okay (he won't come back to this initial question ever, because we as the audience know about her state anyway). This dialogue is almost painful in it's pragmatic efficiency. This is the first time that Claire gets a real introduction, so this introduction - along with a thinly veiled nod to "Daredevil", where she has a more pronounced role - is given here. Both of them are acquinted to superheroes. Great. We as the audience already know, so it needs to be established quick here, and quickly it's done. But really, think about this for a second.

Claire is saying that she "runs into special". Yet she doesn't know Jessica, Luke or the big bad of the show, Kilgrave, who can mindcontrol people. So who is she talking about? We know, of course, it's Daredevil, but Malcom doesn't. Given that they are repeatedly threatened by these superheroes and their enemies and that it's also a point of general interest if you know these guys, Malcolm's glib indifference to Claire's acquintances is strange. But of course, the whole thing here had to be brought out of the day as quickly as possible, because the dialogue is there solely to serve a narrative purpose: a contemplation about the effect superheroes have on people and to give Malcolm and Claire some rationale to do what they do.

So, what do they say? "Can't change what we know" and "Yeah, I miss ignorance too". And yep, this would be considered pretty solid writing for a column in the New York Times, where a writer reflects about the fallout from "The Incident" (the events of "The Avengers") or some such, but this is a dialogue between two people who have met like literally 30 seconds before. It's not at all believable as a character moment. But that's to be expected, because neither Claire nor Malcolm are characters; they are functions. Brace yourself, it's getting worse. 

Claire: [chuckles, puffs up Luke's pillow, takes his blood pressure]
Malcolm: Wasn't that long ago I was trying to get my degree in social work.
Claire: Wanted to help people?
Malcolm: I still do.

Malcolm

Wait, what? How can you get anymore cliched in about ten seconds than this? Not only does Claire perform some pretty nonsensical tasks here that just give her something to do and emphasize her caring nature, Malcom without any connection talks about his plans before meeting Kilgrave (who Claire still knows practically nothing about), which conveniently allows Claire to explicitly state the motif of the whole scene: helping people, how you do it, and how it affects you. But remember, this isn't about either Claire or Malcolm, who are just functions, so of course this serves only as a thin explanation for why they sacrifice everything for Jessica, and the talk returns to her.

Claire: Well...don't need powers to be of use.
Malcolm: I don't want powers. I mean, I don't want to be on the receiving end of them either, but...I don't know, I just like people too much. Luke, Jessica, just by necessity, by definition, they're seperate. Even from each other.
Claire: Maybe that's why they need us so much. Connection.

Yeah, I get it. Nurses, they're the real heroes. It's a truly extraordinary step the show is taking here, because no one ever made the same point before in a movie or a campaign speech. It's so banal, it's laughable, especially given the efforts of the actors and writers to try and make this profound. But again, it's not about Claire, so back to Jessica and Luke, who need "a connection", because they're seperate. Just in case you hadn't understood it in the last twelve and a half episodes, here it's spilled out explicitly once again. This is stuff you need to show, not to tell.  

Malcolm: What does that make us? Sidekicks?
Claire: Oh, I'm no one's sidekick.
Malcolm: [grins] I can see that. Jessica's got it in her, you know? She may well never find it, but it's in there.
Claire: An alcoholic?
Malcolm: A hero.
Claire: [mouthes incredoulesness] Tough business.
Malcolm: So is yours. Why don't you take a break for a while? I watch him.
Claire: [sighs, looks at watch in indecision, finally smiles and walks away] Thanks. You're not a...mind-controller, aren't you?
Malcolm: Kilgrave. Evil prick.
Claire: [raises hands, sighs] Ok. I'll be on the couch.

We close the scene with a genre-savvy discussion of what they are (sidekicks, yes, that's exactly you're function, nothing more, thanks for saying that out loud), what Jessica is (a hero) and what Kilgrave is (the villain). There is a certain need to spill it out like this, because the show repeatedly fails at showing what it ostensibly wants to tell. There's a disconnect between the text and the rest of what's happening, which is one of the central problems of the show.

"Evil prick" Kilgrave

These two minutes of dialogue serve very well to show why the pieces don't click together. Never in these lines is there a feeling that it's spoken by real, breathing people. Yes, it's not written language - which is the problem of the really worst dialogue you can find - but it's painfully obvious, on the nose and totally detached from any humanity of these people. It's purely an outflow of function. The show at some point needs to adress these issues, and since neither acting nor writing managed to pull that off implicitly until now, they hamfisted it in.