I don't know. I find Mycroft's behaviour a bit off at the christmas scene. He says 'there's something in the punch' and you don't see him drinking it, this strange admission, the fact that he didn't see through Sherlock's plan, the 'job offer', and he was outside when everyone was collapsing, looking entirely normal. Maybe it's nothing and I'm just paranoid but I've learned not to trust the Moftiss too much. 

I think the 'your loss would break my heart' sets up the helicopter scene, and makes the suicide mission even more painful.

There's something even stranger than that line: in his last scene, he actually smiles. 
 

My favorite part of the episode. I just love their interactions. 

Yes; I really liked their interactions. I felt that this was a counter balance to the emotional weight of John and Mary's connection to each other; after gratuitously tugging on our heart strings with Sherlock disappearing alone into the night after the wedding, it felt good to know that Sherlock had somebody who really cared for him.

And it avoids the dreadful prospect of it turning into 'John, Mary and Sherlock solve crimes together' show which, if not actually breaking my heart, would certainly fracture my temper...

I had (have) my doubts about Mycroft involvement: such a daring plan to bring down Magnussen seems something both brothers would plot together. On the other hand, initially Mycroft seems genuinely displeased that Sherlock goes against Magnussen and he thinks M. has his "utility". This difference of the approach shows the difference in mentality of the brothers, as well. As for M. saying to S. he cares about him, I find it plausible, since he had almost lost his brother recently. Furthermore, from the narrative point of view it is the preparation to the emotional scene in the end, when Mycroft panics and shouts "don't shoot Sherlock Holmes!" and then says "Oh Sherlock, what have you done!". He knows he just has "lost" his brother and it is breaking his heart.

After watching HLV several times (okay I am a bit slow) I can't help thinking that Mycroft was either in on the plan or -perhaps more likely- knew about it and did nothing to stop Sherlock because that's just what he wanted. Therefore his remark about Sherlock's "Utility". Also CAM mentions that Mycroft was waiting for an opportunity to get to CAM for years and he now must be a very proud big brother. So it's not Sherlock who is using Mycroft but the other way around. Of course, the plan goes wrong because Mycroft did not foresee that Sherlock would kill CAM. I think he is genuinely shocked and for a moment out of his depth because even for Mycroft it is very difficult to help his little brother in this situation ("Oh Sherlock, what have you done?").

By the way Sherlock's reaction to the utility-remark broke my heart a little.

Mycroft's admission was out of character, that's what made it so moving.  It showed that even the rock solid Mycroft had been affected by Sherlock's 2 years on the run.  We know he's always "worried" about Sherlock but, imagining what he had to face in taking down Moriarty's web, those 2 years had to push Mycroft's nerves and resourses further than ever before.

I think it was just said so that it set up the foudation for you, the watcher, to understand how he feels about having to punnish his brother.  So when we see that he sends Sherlock off, we know it's killing him to do so. That shows just how SERIOUS he takes his posission.  

I did enjoy the fact that this season had A LOT more Mycroft inneraction in it. 

Something not mentioned here I have been wondering about is the call Sherlock makes  to Mycroft in TSOT.
Unusual for Sherlock to call him, but as they have been getting on better this series kinda nice that Sherlock seems to want him at the "night do"

But Q's....Why didn't Mycroft go..and why even back then does he seem to be warning Sherlock not to get involved  it will all end in tears..mentioning red beard.
Hmm
Been thinking Mycroft already knows about Mary back here..and if so either he researched, or he planted her as a idk bodyguard type...
Idk just some ideas...they did say back ep1 Mycroft did cia work on a freelance basis , and Mary also cia , freelance mentioned so a link maybe.
Or if he did research her..did he find the link to CAM, but then no he wld of seen the danger coming...or maybe he did hence red beard comment.
Or maybe he just thought mary could never be a pressure point to him via Sherlock...still don't get that...
Eh well I keep going in circles with it as you see, any thoughts?

The whole scene seems to be a mirror image of the midpoint scene in Scandal (which, incidentally is my favorite scene of the whole show). Both scenes show how much Mycroft really cares for Sherlock, only the first time it was subtext and the second time it was said out loud.

I loved the irony in the 'caring is not an advantage' line in the first scene because it'd never been so obvious that he cares before. For both characters, that theme keeps coming back, they want to be detached and objective, but they can't because they're human. 

I do kind of wonder why Moffat felt the need to spell it out for us, he's so good at subtext. Maybe just to remind us in case we'd forgotten? Or to take the character of Mycroft a bit further, the first time he'd probably rather die than admit it, maybe something changed for him, Sherlock's injury perhaps.

I'm also really curious about what Sherlock will do with that information and the exile thing. I think he'd lose trust, if he had any to begin with. Not really what Mycroft wants, he probably does care, whatever real meaning his decision has. Would be interesting to play with that dynamic. 

lil wrote:

Mentioned this before somewhere I think...but some more thoughts......I don't think that convo was about what it seemed. Tho its my fave.

I think they are planning the op to take down cam.
Cam is the dragon, like in canon dragon is the safe.

Mycroft reading the paper about the Smallwood suicide ..he changes his mind on the cam threat.
Smoking convo. They set up the op...slay the dragon...the dragon being Magnusson and hence John the damsel in distress and sherlock the dragon slayer.
Sherlock didn't betray Mycroft they plan it right here.
Thats why Mycroft has the laptop handy and drinks the punch.

I think the break my heart comment is Mycroft offering to have Sherlocks back...they must suspect mind palace when no google glass.
Nevertheless I think Mycroft is shocked that Sherlock can't complete the op without killing cam.Hence the oh Sherlock.

Sherlocks shouting to Mycroft just before he shoots translates to me something like....there's no vault/ evidence to set him up...we got it wrong..now look
What I have to do...get ready to have my back.

And Mycroft does.

I like this train of thought, would make "Mike" more human.
Often he seems so devoid of emotion (on the surface, who knows how troubled he is inside), this would show he isn't.