Adult Sheldon: Since I no longer had a college class with Dr. Sturgis to stoke my intellectual fire, I needed to find someone else who was up to the task of being my mentor. A great mind. A once-in-a-generation thinker. Fortunately, my schedule was wide open.
Sheldon: School's in session.

Sheldon: Missy and I broke a lot of rules the other night, and we've received no punishment.
George: [sighs] Buddy, it's been a rough week. We're just glad you're both safe.
Sheldon: But in the absence of a divine being, society's rules are what keeps a person's morality in check.
George: Well, there you go.
Sheldon: No, y-you're not following me. If actions have no repercussions, society breaks down, everything devolves into chaos.
George: You might be overthinking this.
Sheldon: I thought so, too. Then I thought about it, and I'm not.
George: Sheldon, you had one bad night. Just let it go.
Sheldon: But... I did something wrong and I got away with it. That's not okay.
George: Buddy...
Sheldon: Socrates maintained that the man who lies to himself has an enemy living within. He's not even a person. He's just a chaos of selfish desires wrapped in an animal hide.

Ms. MacElroy: Now, can anyone tell me why Melville shifts the narrative voice from Ishmael to Ahab? [Ms. MacElroy waits for somebody else to raise their hand] Sheldon.
Sheldon: I have a tummyache. I'd like to see the nurse.
Derek: A "tummyache"?
Sheldon: Yes, Derek, I have a tummy and it aches. Ergo, tummyache.
Derek: Ergo?
Sheldon: It's Latin, Derek.
Ms. MacElroy: Go to the nurse.
Sheldon: And to answer your question, the shifting point of view grants the reader a broader perspective of events than typically allowed by first-person narration.
Ms. MacElroy: Where were we?
Sheldon: And "ergo" is Latin for "hence," Derek.

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]

George: Hey, Hubert. Was Sheldon in class today?
Mr. Givens: Nope. Haven't seen him all week.
George: Weren't you gonna say anything?
Mr. Givens: I didn't want to jinx it.

[Sheldon is chuckling as he stares at a blank screen]
Missy: What are you doing?
Sheldon: Watching last week's Professor Proton in my mind.

George: So he hasn't been in any of your classes?
Ms. Ingram: Mm-mm, not a one.
Ms. MacElroy: Nope.
George: But I bring him here, I take him home he's got to be somewhere in the building.
Ms. Ingram: Mm, I might've seen him in the library. But at this point, I sometimes think I see him when I'm alone in my house.
Ms. MacElroy: Like that creepy Chucky doll in the movies?
Ms. Ingram: [laughs] Exactly!