Adult Sheldon: My mother didn't believe in elves, fairies, or dragons. But she did believe in the devil. And she did not view him as an appropriate playmate for her son.

Adult Sheldon: I've been called a germophobe, but I do find a single sneeze acceptable. It could be caused by dust, allergies. Really, whatever nasal irritant floats your boat. However during flu season a second sneeze means a plague is upon the land, and it's every man for himself.

Adult Sheldon: Enjoy this. It is, by far, the most athletic two minutes of my entire life.

Adult Sheldon: It's called perfect cleavage when gypsum separates this cleanly. I was so proud of Tam for not making an immature cleavage joke.
Tam: Look at me, I'm touching cleavage.
Adult Sheldon: Until he made one.

Adult Sheldon: And, like Mother Nature's piñata, geodes contained a secret surprise inside. But you didn't have to suffer through a birthday party to enjoy it.

Adult Sheldon: The perilous journey from the bus stop to my front door was 97.5 meters. FYI, insisting on using the metric system in East Texas is another reason I was hunted by predators.

Adult Sheldon: When people wonder why Radio Shack eventually went out of business, you can point to this moment.

Adult Sheldon: In physics, nothing feels better than predicting an outcome. I love predictability. The force of gravity: predictable. Nuclear fusion: predictable. My brother peeing in the shower: repulsive, but predictable. What isn't predictable: dogs. I've always been terrified of dogs. To me, they're nothing but big, furry question marks. Question marks with teeth.

Adult Sheldon: I would go on to draw up such contracts throughout my life. With roommates. With my wife. Even with my own children.

Adult Sheldon: My father's wisdom touched me deeply. Which is why, to this day, no matter what I'm going through, I am never irritating or abusive to any of my friends or loved ones. Ask them. They'll tell you.

Adult Sheldon: Not since sharing a uterus with my twin sister have I been so unhappy sitting next to someone.

Adult Sheldon: In tenth grade, high school students are presented with picking a class of their own choosing. This is called an elective. Courses on offer included wood shop, I'm happy with ten fingers, thank you; introduction to agriculture, I think you know the answer to that; wrestling, I'd rather milk that cow. All of which led me to the elective I reluctantly chose, Psychology 101, an investigation into why people think and feel the way they do.

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.

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

Sheldon: State troopers. I wonder what they want.
Adult Sheldon: It turns out they wanted me. Fun fact, this was one of seven times I was brought home by law enforcement once, on the back of a horse.

Mary: Baby, you need to eat something.
Sheldon: But it looks like I can change the definitions of electric and magnetic fields and rotate the magnetic charge away mathematically to zero.
Mary: Maybe some fried okra would help.
Sheldon: Richard Feynman didn't develop quantum electrodynamics by filling up on fried okra.
Mary: Well, maybe that's because his mama didn't love him as much as I love you.
Adult Sheldon: Richard Feynman was Jewish. His mother didn't give him fried okra.

Adult Sheldon: Having found no answers, I took it upon myself to rectify the inconsistent timeline in Lord of the Rings. J.R.R. Tolkien had a brilliant mind, but let's be honest. He was no S.L. Cooper.

Adult Sheldon: Thanks to Dr. Sturgis, I had all the intellectual ammunition I needed to bring my opponent to his knees. I accused him of conflating two different interpretations of quantum theory, woefully misrepresenting Paul Dirac, and when I called him a dung beetle in Latin, I was so riled up, I almost started producing testosterone.

Lisa: [modem screeching] What's that noise?
George Jr.: No idea.
Sheldon: Georgie, I need you to get off the phone.
George Jr.: Hang on, Lisa. I'm helping someone with their English homework.
Sheldon: I don't have time for jokes. I need the phone line to connect my modem.
George Jr.: What the hell's a modem?
Sheldon: It links my computer to an interconnected web of other computers in order to facilitate the exchange of ideas.
George Jr.: That's the stupidest thing I've ever heard of.
Adult Sheldon: Sadly, that was not the stupidest thing he ever said.

Sheldon: [answering phone] Cooper residence.
Dr. John Sturgis: Hello, Sheldon.
Sheldon: Dr. Sturgis. I'd love to talk to you, but I'm right in the middle of Star Trek: The Next Generation. It's a good one. Geordi goes missing, but Wesley Crusher has a plan to use neutrinos to locate him, since they'd be visible to Geordi's visor.
Dr. John Sturgis: I was actually calling to speak to your father. But I'm glad you're having fun with your friends.
Sheldon: Hang on. I'll go get him. Dad! Phone call!
Adult Sheldon: Even though Dr. Sturgis was confused, one day, Wesley Crusher really would be my friend. Neat, huh?