Sheldon: Excuse me, I was hoping to purchase some practical joke paraphernalia so that I may behave childishly.
Glenn: Rack in the corner.
Sheldon: Thank you. "If it's funny, it's a Bazinga." Interesting.

Sheldon: I started working on this presentation to address specific ethical dilemmas. The laws of robotics, whether torture can be justified, and cloning people for fun and spare parts. But I realized before resolving any of these moral quandaries, the real decision is who gets to decide. Do we put it up for a vote? Does everyone get to decide for themselves? Should it be by committee? Is that committee elected or appointed? You see where I'm going? You probably don't. For the smartest decision, we need the smartest person. Ladies and gentlemen, in the field of scientific ethics, we can't rely on democracy or plutocracy. We need an autocracy, or to be more precise, a "Sheldocracy." [slams fist] [military march plays]
Dr. John Sturgis: Um, I don't think this was the assignment.
Sheldon: Sorry, Dr. Sturgis, I pick the assignments now. Everybody, for next class, I want 500 words on what you can do to further the Sheldocracy. Punishment for typos will be severe.
Dr. John Sturgis: Class dismissed.
Sheldon: Hey, that's my line.
Dr. John Sturgis: No, it isn't.
Sheldon: Why don't you see me after class. Class dismissed.

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: You understand that some people are going to be intimidated by you, because of how smart you are?
Sheldon: Or maybe they'll recognize my intellect and make me their leader.

Adult Sheldon: And that's how I became the madcap prankster all my friends know and love.

Paige: You know, I read that adults who had a stunted childhood often become social misfits and weirdos.
Sheldon: You didn't read that, you're making it up like your goat story.
Paige: Psychology Magazine, February issue, 1988.
Sheldon: Well, um, that doesn't make it true.
Paige: Guess you'll find out when you're an adult.
Sheldon: I guess I will.
Adult Sheldon: Well, we know how this story ends. I grew up to become a well-adjusted and charming fellow. But at that moment in time, she had me worried.

George: So, John, how was your first driving lesson?
Dr. John Sturgis: Intense. At one point, I was approaching an intersection. The light was green, but at the last moment, it turned yellow. I didn't know what to do. Should I keep going? Should I stop? There were other cars nearby. Connie was yelling. A glare from the sun was in my eyes.
Sheldon: So, what happened?
Dr. John Sturgis: Somehow, I managed to make it through, turned on my directional, and slowly pulled to the side of the road.
Sheldon: That's how you tell a scary story.