What event or incident do you think would bring the emotionally barren Sheldon to his knees?

I personally think that one of the big reasons Sheldon is this way is because of his childhood. Of course he is Sheldon, he's very eccentric and him being closed off emotionally is also partially due to his personality.

But he has talked about how his dad was an alcoholic and left his mom for a bartender, and how he tried to change him into the son he really wanted. His mom was obviously devestated from the whole situation and turned to religion because of it. I think Sheldon, as a kid, probably closed himself off to emotions and intimacy because of this, to protect himself. Notice how he freaks out when people start yelling at each other and fighting.

I think Sheldon is interesting because so many people say he's asexual, but he's actually not. Humans can't be asexual. He's celibate, which is a choice and not something that is just a part of you, and again I think this just is a symptom of his unwillingness to break down the mural to his emotions.

Childhood trauma can really affect people and I think that's the root of a lot of his issues. Sheldon is human, he's not a robot, and noone can convince me that he could go through what he did as a kid and not be affected.

I think that him losing any of his close friendships, which have actually helped him evolve so much as a character, would be devestating to him, because of his past and the way I think he really counts on his friendships and relationships without even knowing it. Sheldon is evolving, he's not the same person he was in Season 1. And that's because of his relationships with these characters. They've all changed and had an effect on each other. I think Leonard, Penny, and Amy have been most influential on Sheldon. I think anything happening to those three relationships would be very devestating, whether it's b/c something happens to one of them or Sheldon is cut off from them somehow.

I see those three as like the three tiers of relationships that Sheldon has come to rely on. Leonard kind of introduced him to the world of real friendship. And Penny really expanded his world. She was unlike anyone he usually was surrounded by, it was like a new perspective. And Amy is his first romantic relationship, and she gives Sheldon conselhos and kind of balances some of Sheldon's mais extreme qualities. Leonard, Penny, and Amy are always the people he turns to for advice. He's definitely the closest with those three. So they are the key to breaking down Sheldon's defences IMO.

Death of his meemaw, or his mother, or any of his friends would do it. He's human, after all.

A less extreme possibility is if he's in a situation where Leonard, Raj and Howard aren't there for him. For a long stretch of time. I think he'll finally realize how much he needs them. (There have been some precedents, but none of them was permanent.)

^Agreed. But there's also one much mais simple and easier example.

Do we all remember how Sheldon was when he couldn't finish his sentence?

Or....

When it hits Sheldon that he's not the smartest person alive. XD

That is true

"No one calls me Moonpie but Meemaw"

A lot of things could. lost of a amor one, an accident, his friends leave him, Amy breaking up with him, his início being gone, his childhood bully comes back and so on.

i think he wood lose it if either meemaw or leonard nemoy died...his meemaw bc well its his meemaw and shes ta only one tht can kall him moonpie :) but he wood lose it w/leonard nemoy bc he wood realize tht he has ta napkin 2 make a clone...

I think meeting leonard nemoy

Sheldon could be brought to his knees if he'd realize that he can no longer supress his desires and he starts falling in amor with a woman, a.k.a Penny.
Maybe a kiss would help. Sheldon Cooper would have to deal with the fact that he's not Vulcan and that he too, can experience feelings of true love. So instead of death, I'll go with love.

I think Sheldon would crack if he was fired from the University, his Meemaw died or if Leslie Winkle won the Nobel Prize. :)

I totally think the death of his Meemaw would do it or another family members or friends.
Also maybe if someone did something he really didn't like such as destroying all of his collectables, like when penny and him are at war basically and they are both sabotaging each other if penny had gone in and opened all the figures he has in the boxes or drawn in his mint condition comics like she said she would, or destroying all of his research, like when they all comeback from the north pole and Howard and raj reveal that they tampered with his work he was pretty bumed out so maybe if it turned out all of the work he had been doing his whole life was tampered with that may do it.
Just a few ideas :)
Oh and maybe if something were to happen between him and Amy? I don't know that one was a last minuto thought :)

If someone roubou all his comic books definitely

I think it will be when one of his friends becomes mais of a smart-alic than he is! I'd amor to see that! =)

death of MeemMaw for sure

Either seeing Amy with a guy smarter than him, or his " Meemaw " dying.

Stan lee dying

Um... several,
When that genius kid was smarter then him, uh... When they were robbed... Um... Darn I hate it when Im about to say something then I forget what to say.....

If he met Marilyn furgão, van Savant

If his memaw died