Sheldon: One interpretation would be, if I was standing at the event horizon, I could interact with my own twin.
Missy: I've interacted with you. It's not great.
Sheldon: I think if there were two of me, we'd be unstoppable.
[fantasy:]
Sheldon #1: So, if we add the information entropy, we'll get the result we're looking for.
Sheldon #2: That's brilliant.
Sheldon #1: I had a feeling you'd like it.
Sheldon #2: That's what the back of my head looks like. Nice.
Sheldon #1: Hmm. We'll call it the Cooper-Cooper Theorem.
Sheldon #2: Perfect. Wait, which Cooper comes first?
Sheldon #1: This Cooper.
Sheldon #2: Why you?
Sheldon #1: I'm the original. You're just my twin.
Sheldon #2: Don't say it like you're better than me. We're exactly the same.
Sheldon #1: I don't appreciate your condescending tone.
Sheldon #2: It's your tone. We're the same person.
Sheldon #1: If we're the same person, why are you so annoying?
Sheldon #2: Stop it.
Sheldon #1: You stop it.
Sheldon #2: What are you gonna do about it?
Sheldon #1: I don't know, I've never been in a fight before.
Sheldon #2: Well, you're about to be.
[reality:]
Sheldon: This is ridiculous. Are you done?
Missy: Not even close. Then Sheldon One grabs Sheldon Two...

Principal Petersen: Our next young speaker needs no introduction, but that didn't stop him from writing one and making me read it. [laughter] "Fun fact." [audience groans, murmurs] I hear you. "The word 'valedictorian' is from the Latin 'valedicere,' meaning 'to say farewell.' It is primarily used in the United States, Canada, the Philippines and Armenia." Maybe that fact's more fun in Armenia. Please welcome your valedictorian, Sheldon Cooper.
Mary: Yay, Shelly!
Sheldon: Hello. I'm not very comfortable speaking in front of crowds. But there's a technique to reduce stage fright by focusing on one person in the audience and delivering your speech just to them. That's what I'll be doing today. If it weren't for this person, I wouldn't be here right now. They've taught me a lot, and it's by their example that I found the courage to move forward into this new and exciting chapter of my life. Missy... ...this is for you. Change can be scary, but I know we're going to be fine... ...because like you said, "It's okay to be scared. We just have to do it anyway." So if any of my fellow graduates are nervous about the future, know that you're not alone. I suggest you all try to be as brave as my twin sister. That's my plan. Missy, I wish I could give you advice about middle school, but I was so smart, I skipped it. If you make it to high school, we'll talk. Thank you. [applause]

Mary: Sheldon, faith means believing in something you can't know for sure is real. And right now, I am struggling with that.
Sheldon: So you don't believe in God anymore?
Mary: That isn't something for you to worry about. I need to figure this out myself.
Sheldon: Can I help? Maybe I could provide a fresh perspective.
Mary: I don't think so, baby.
Sheldon: Did you know that if gravity were slightly more powerful, the universe would collapse into a ball?
Mary: I did not.
Sheldon: Also, if gravity were slightly less powerful, the universe would fly apart and there would be no stars or planets.
Mary: Where you going with this, Sheldon?
Sheldon: It's just that gravity is precisely as strong as it needs to be. And if the ratio of the electromagnetic force to the strong force wasn't one percent, life wouldn't exist. What are the odds that would happen all by itself?
Mary: Why are you trying to convince me to believe in God? You don't believe in God.
Sheldon: I don't, but the precision of the universe at least makes it logical to conclude there's a creator.
Mary: Baby, I appreciate what you're trying to do, but logic is here. And my problem is here.
Sheldon: Well, there are 5 billion people on this planet and you're the perfect mom for me. What are the odds of that?

Missy: What's it like to not believe in God?
Sheldon: It's great. Big fan.
Missy: Are you ever afraid you're wrong?
Sheldon: About religion? Never. About other things? Also never.

Adult Sheldon: [v.o.] We often regret the things we don't say. There's a lot of things I wish I had said to my dad while he was around. That I appreciated him. That I loved him. Which is why I'm grateful for the times I did tell him how I felt.
Sheldon: Tonight was fun.
George Sr.: Yeah? Why is that?
Sheldon: Dr. Sturgis was here. Everybody talked about science. It was nice.
George Sr.: It was.

President Hagemeyer: Sheldon, Dr. Sturgis quit right before the semester started. He left me in the lurch.
Sheldon: And this is your chance to be the bigger person.
President Hagemeyer: I don't want to be the bigger person. I'll be the small, petty person. That's way more fun.
Sheldon: Please? It would make me really happy if he came back. And you said yourself my happiness is important to the university.
President Hagemeyer: Are you trying to manipulate me?
Sheldon: Hey, being small and petty is fun.

Meemaw: Thanks for inviting John to dinner tonight.
Mary: Oh, my pleasure.
Meemaw: I've been a little bit worried about him. You know, with what happened last time.
Mary: At least he didn't seem unstable when I talked to him.
Meemaw: The man has a doctorate in science, and he's filling people's grocery bags.
Mary: He actually did a really nice job. He put the heavy things on the bottom. He kept the cold things together.
Meemaw: Mary.
Mary: Well, they don't always do that.