I have things I should probably say, and stuff, but instead... I have a bizarre essay-ramble-with-pictures on Mac/Guy, and why it makes sense, and why I love it. (Possibly less of the making-sense bit, actually.)
It does contain spoilers for both series and the special, and is probably not that dial-up friendly.
Erm, for the benefit of anyone unfamilar with the characters but is still planning to read anyway. (You are insane, incidentally, although do go ahead. Maybe you'll end up watching Green Wing! Who knows.)
Meet Mac
Smooth-talking, floppy-haired surgeon with unknown first name.
Likes: The Kinks, motorbikes, haircare, glass lifts, toast, electronic swipecard entrances, opera.
Dislikes: Sweetcorn, accusations of being ginger, being reminded of broken relationship with Holly The Baby-Killer.
Superpowers: Amazing hair, effortless and transcendent coolness, wit.
Weaknesses: Inability to express feelings for Guy.
Meet Guy
Self-worshipping anaesthetist; abandoned at a ski lodge as a child and currently taking it out on the rest of the world.
Likes: Switzerland, Bentleys, Toblerones, being a twat, Barry White, Elton John, Queen not any more.
Dislikes: Books, baseball caps, losing at anything at all.
Superpowers: Womanising prowess, Guyball skills.
Weaknesses: Fear of doing the right thing, inability to cope with love.
The Banter
Being manly men, Mac and Guy often find they have to express their love in the manner of eleven-year-old boys who aren't quite sure how to tell a girl that they quite fancy them: that is, pretending that they absolutely don't, and in fact don't like each other very much. (This strategy falls at the first hurdle in that they appear to spend pretty much the entirety of their working days together, even when they don't have to, aww.) They spend most of their time arguing--
MAC: So, tell me, why are you wearing a blouse?
GUY: What?
MAC: It's a blouse, isn't it?
GUY: Fuck off! It's designer.
MAC: What, Laura Ashley?
--trying to assert their superior status--
MAC: You're my anaesthetist.
GUY: No, you're my surgeon. You're my surgeon bitch.
--playing stupid games--
(Mac gets Guy to eat coffee)
(the Spoon of Destiny)
(they race across a swimming pool)
(and try to headbutt signs in the corridor, which it turns out is very difficult to cap in any way)
--and irritating each other as much as possible.
GUY: Fucking Mac! I know he fucking gets to the fucking canteen before me, and he takes all the fucking jelly and hides it, because he knows I fucking like it!
Guy boasts to Mac, all the time, about everything (in, I imagine, an ill-concealed attempt to impress him), but is usually met with a witty repost.
GUY: I could happily kill everyone with a baseball cap.
MAC: One baseball cap?
GUY: I can do a surface dive in my pyjamas.
MAC: That's probably very handy for a bedwetter.
He will then tend to have a go at Mac's hair as compensation.
GUY: You... are a gingre.
MAC: I am a fraise-blonde.
Their general relationship is therefore one of comfortable friction (no, that does not make sense, I do not care), constant bids for one-upmanship, and, possibly, mutual, grudging respect, although they wouldn't show it for the world. Over the two series and the special, though, there are a few incidents worth noting.
The Fight
This essentially sums up Mac and Guy's statuses (statii?) as, respectively, Resident Moral Compass and Resident Wanker, and is also quite a good excuse for them to grope each other.
Guy has played a rather horrible and tasteless joke on Martin (junior doctor, hopeless case) which has resulted in him breaking down and crying in the corridor. Mac finds out and storms off to confront him (apparently indignant at Guy's mistreatment of Martin, although possibly using it to get across some of his jealousy at Guy's attempts to woo Caroline). Mac, usually near-impossible to ruffle in any way, snaps and pours cornflakes over his head--
--gets a hugely ineffective bitchslapping from Guy in return--
--before a bit of a chase through the hospital, culminating in them wrestling on a table in the canteen.
Hatred or love? Quite clearly both. Possibly.
Guy Letting Slip
GUY: I want Mac struck off. He's gay and I've got proof.
GUY: [gesturing to surprisingly well-endowed naked painting of Martin on the wall] You know, if he's that size...
[places fire extinguisher on table]
That's me.
[places small cactus on table]
And that's Mac. And I know that, because I watch him when he showers.
[slightly shifty, "I-really-shouldn't-have-said-that" look]
GUY: Anyway, I'm part of your relationship.
MAC: How?
GUY: Erm, I've slept with both of you.
MAC: Not... so much.
GUY: Well, with one of you.
CAROLINE: You really haven't.
GUY: Haven't I?
CAROLINE: No.
GUY: Do you know, I really thought I had.
CAROLINE: No you didn't.
GUY: No, I didn't... but I have slept with Mac, haven't I, back at college... he missed his mum so he crept into my bed, crying.
MAC: We didn't go to the same college.
GUY: I thought it was a long way to creep. Anyway, how could I turn him down... that pouty ginger face, freckly little back, those hairless little nuts, scabby little knees...
CAROLINE: You put just a little too much thought into that, didn't you?
GUY: ...yeah.
As well as coming out with unexpected details on Mac's intimate regions now and again, Guy will--very rarely--accidentally show that he cares. He does! A tiny bit! He keeps going to visit Mac when he's in a coma--
--and, for about ten seconds, suddenly goes all serious and upset (and incomprehensible).
GUY: Mac, I... I just want to say that... I haven't... I wasn't very... I haven't, I wasn't, I didn't...
JUST SAY YOU LOVE HIM, GET IT OVER WITH, FOR GOD'S SAKE. He then goes to extreme, if bizarre, measures to revive him--
GUY: Wake up, or the kitty gets it!
MAC: [stays in coma]
GUY: [to kitten] You said that would work!
--and then he gets banned from seeing him ("Bann-ed? They can't ban me!"), but goes anyway and even (very badly) disguises himself.
Guy also defends Mac to Caroline when they meet at the station at the end of series two.
GUY: Where's Mac?
CAROLINE: Well, he's let me down again, hasn't he. Life's just a game. Bastard.
GUY: Well, no... I'm sure he has reasons. He's actually not a bastard, he's, erm, he's a really good bloke.
See, Guy can say what he likes about Mac, but the moment someone else has a go? LEAVE MY GINGER ALONE.
Mac Letting Slip
If Guy is terrified of showing anyone he has genuine feelings of any kind, Mac would probably like to, but is pretty much incapable of doing so. Apart from repeatedly scuppering his relationship with Caroline--bottling everything up meant that he handled the Holly situation terribly--it means he very rarely says anything nice about Guy, ever, because he's far too good at being cool all the time. As in he really is too good at it, the poor thing.
When Guy has to take time off from work to do community service, though, Mac and Caroline try to pretend they don't care--"It's great without Guy, isn't it?" "Mm, it's we're like proper doctors." "All grown-up and sensible,"--but come to realise that they really miss him, and try to get the supply anaesthetist to fill his shoes--"Can you just say something really twattish?"--and eventually get him to wear a donkey mask to make up for Guy's absence. See, there's some love there.
Also, comatose!Mac is apparently not quite as good at hiding his feelings. When Guy talks to him, what image does he conjure up? THEM, WRESTLING, HALF-NAKED. You see.
The Illness (or, insane overuse of italics convey the sincerity of feeling)
MAC: Talking of honesty, I, erm... there's something I... I have to tell you. Er, have to tell someone. Which is... erm. Mmm. Um, I... I'm dying.
GUY: What?
MAC: I'm dying.
GUY: What?
MAC: I'm dying.
GUY: Are you trying to tell me that... what?
It takes him bloody long enough to get it out, but the first--and, as far as we know, only--person Mac ever tells about this is Guy. You could argue that he has to get it off his chest, and Guy just happens to be the nearest person to tell, but he still chooses him, and he plans it all, he seems to have taken him to a bar and got him very drunk in preparation for the whole thing. If he did purely need to tell anyone, wouldn't it be a better bet to go for, say, Boyce? Someone relatively sane and kind who would probably be supportive? But he doesn't. He chooses Guy.
And Guy responds as only Guy can, which is mainly, "What? What?" for some time, followed by a jibe about being ginger, and some stuff about acne, and it's a combination of extreme intoxication and (I like to think) fear of expressing the fact that he is really, really upset. And for a few minutes, in the middle of the scene, he forgets to pretend that he doesn't care.
GUY: [looking at the name of the illness Mac has written down] Shit. Oh no. How long have you got?
MAC: Yep. Just a few, er, just a few weeks.
GUY: You're joking.
Then it cuts to Guy's face, and he is dejected, utterly, utterly dejected, and it breaks my heart.
And then it cuts to Mac, and he's crying, and then he turns it into a laugh, and my already broken heart is stamped on, repeatedly. They dissolve into hysterical, devastated laughter.
GUY: You twat! Why are you dying?!
MAC: [head in hands] I don't know.
GUY: Actually, I wish I was dying. I bet I'd be better at it that you are.
MAC: I wish you were dying.
THEN THE SCENE CUTS AND I COLLAPSE.
There's also a beautiful little deleted scene in which Guy bounds over to tell Mac that he's found a cure for his illness, and he is so happy, and he's put work into researching it and everything. (It turns out he was researching the wrong illness, but THE THOUGHT AND LOVE WERE THERE.)
Other, unconnected pictures:
Synchronised yo-yo action.
LOOK SYMBOLISM
Outtakes: Guy attempts to pull comatose!Mac's trousers off.
And then kisses him. I maintain that this was fully in character.
And a final note for those of you who think I am utterly delusional (from the GW BFI talk):
VICTORIA PILE: When we started the second series, we didn't actually know how it would go, whether Caroline would end up with Mac or Guy... we even toyed with the idea of pairing Mac and Guy up at the end instead...
ME: A'LDFSAKN;LDSGJHDSGUHDGS
So there you have it. Even Victoria Pile was lured by the concept.
I think my conclusion is: Mac/Guy = so much love, and why does no-one write it?*
*Er, excluding the people who have replied to this saying, "Actually, I have written it, look." HOORAH.