Yes@Susie...totally agree..Sherlock seemed quite vulnerable at that moment..you could get a car..a train...a plane...etc . I was a bit awww for him.So uncharacteristic.
With John blaming Mycroft for TRF...seems likely it was Sherlocks invite too, which makes Mycrofts non attendance surprising.
Instead of reassuring him..Mycroft gives him the warning...and thats when Sherlock seems to reconsider everything...and begin deducing everything..ominously.
I do think Mycroft links all the coincidences together and hints Sherlock about things both here and in HLV..in a I cant get involved or tell you government secrets...but I am telling you..in Holmespeak... way.

Random silliness.

At some point in that wedding phone call I really wanted Sherlock to say "Mycroft, you know there's cake........................." 

Tinks wrote:

Russell wrote:

always thought it was an interesting choice to have Sherlock reaching out to his brother, and what was said/at what point things were 'started' in their minds.  Neat!

 
Sherlock and Mycroft's seemingly stronger relationship is all that's keeping me going right now!!

 
Seriously… from seemingly (and humorously) barely tolerating each other/use each other, to just pretending to hate (and working on helping the other with something), to Sherlock calling him at the wedding, playing games/having a talk about feelings, and everything in HLV…  always found them a fascinating mix.  I just know Mycroft had something up his sleeve with controlling what would happen to his brother at the end there.

maryagrawatson wrote:

Russell wrote:

Seriously… from seemingly (and humorously) barely tolerating each other/use each other, to just pretending to hate (and working on helping the other with something), to Sherlock calling him at the wedding, playing games/having a talk about feelings, and everything in HLV… always found them a fascinating mix. I just know Mycroft had something up his sleeve with controlling what would happen to his brother at the end there.

We don't know what happened during the two years that Sherlock was gone. We are given the impression that Mycroft was following him closely. They might have grown closer because of that. Morever, Mycroft's role towards Sherlock is very much like a parent in seasons 1 and 2. But Sherlock has grown up in season 3 and so their relationship has involved to something more akin to equals.

Mary

 
Oh, of course, and no doubt he was, just skipped over that period.  It felt too casual when Mycroft 'retrieved' him to not have made contact now and then, and the tone of their banters afterwards, too.  Really enjoyed that.

While Sherlock is the most observant person in the world, he sometimes misses things when they pertain to the heart.  One of his biggest misses was Molly's Christmas present.  He nailed everything except that the gift was for him. Then he really goofed up his return to John in the restaurant - no comprehension of the gravity of the situation whatsoever.  He's been learning to be better socially as the series progresses but he still makes miscalculations when emotion is involved.  I love that about the show actually and look forward to those charming, 'Aspergery' Sherlock moments. Yes, I think a lot of the scene with John asking him to be the best man was played for humor; but I also think Sherlock might have been surprised to learn that John considered him a 'best friend' after all he had put him through by being "dead" and the toll it took on both of them during TEH.  I also take him at his word when he said at the wedding that he never considered he would ever be anyone's best friend - so he was genuinely  stunned when John made that declaration to him.

tenderworld wrote:

Well yes, I suppose that's true. But he deduced Irene Adler was in love with him. Just seems incredible he wouldn't know what he meant to John. 

I consider this a concession to ACD's:  "My dear Watson," said the well-remembered voice, "I owe you a thousand apologies. I had no idea that you would be so affected."
 

I think for Sherlock it is easier to deduce people when he is not emotionally involved. Like Irene and also like Molly. John, however, is different and not as easily deduced just because Sherlock loves him. And think of Mary - he spotted from the beginning that something was off with her but he wanted to like her for John's sake and so he closed his eyes to these early suspicions. 

As for the "best man" scene - I think that in spite of his self-regard where his intellectual skills are concerned, Sherlock does not feel liked by people. And most of them do not like him. This is the man who felt he had only one friend.  
Just look at his stunned reaction when Lestrade hugs him, when Anderson clings to him, when John finally hugs him at the wedding. He is absolutely not accustomed to being shown sympathy or love. 
 

Very true. 
He does not like conventions and traditions. Marriage is full of them. 
He does not like to "mingle". There are people at a marriage. 
And maybe he hoped that the marriage would somehow happen without him being involved. Because this means that John takes a final step away from him. I think even non-Johnlockers can agree with that. 
 

Yes, I agree. Being best man is being different from fulfilling such a responsible task. And as for the giving away - very sad.