The thing that really made me not hate TFP like I wanted to was the Molly Scene™.
Like??? That was such a big moment for Sherlock? No matter your ship persuasion (Sherlolly/Johnlock/etc), I don’t see how people don’t see what a MASSIVE step this was?
He had to stand there and save her. Usually, this would something Sherlock would relish, right? The ability to be the hero? The ‘drama queen’? But, this time, you can see the dread in him, when he sees the ‘I love you’ and knows it involves Molly. The take Eurus gives him means he can’t use his brain to save her, he has to use his emotions. He has to tell her loves her. He has to tell another living soul - a living soul he knows loves him with everything and has very little else - that he loves them.
Yes, the task was only to get Molly to say 'I love you’ to HIM but Sherlock KNEW that the only way he could possibly get her to say it would be to say it first… despite the fact it would be the most alien and most difficult thing for him to do?
Not only does he do it, but he says it twice. He doesn’t think his first try is good enough. Poor Molly suffers but manages a reply, but it was plain to every single one of us, Sherlock included, what SUFFERING it was.
And unlike before, unlike when he could happily tell himself he was detached and sociopathic and that was that, he couldn’t say it and not feel the weight of it. He can’t pull a Janine™ anymore… and doesn’t that say something a incredibly MASSIVE about how far he’s come???
Yes, perhaps it’s because it’s Molly - (“I’m not trying to mock you. We’re friends. You’re my FRIEND!”) - but perhaps, just perhaps, Eurus, in making him do this, woke him up to all the 'emotional context’ of his entire life.
He realised he does have the capacity to feel, but that he’s been broken by the actions of his sister; scarred, I suppose. He’s opened the floodgates now though; “Once you open your heart you can’t close it again,” so, he can’t hold in his rage and guilt (and coffin destroying) that ensures afterward; because he’s angry he’s broken, angry and despaired at the situation… but mostly utterly despairing that he had to make Molly suffer, AGAIN… and this time, he felt every single, painful shard of it.
Once upon a time, he hurt Molly on a whim, almost for fun, and would be completely ignorant to it. Now? Well, the change is pretty fucking astounding. Therefore, I would happily label this the most important scene of the episode. It just… says so much with so little?.