Adult Sheldon: I didn't realize until years later that my father was only asking questions about lightning and thunder to cheer me up. In fact, he would often pretend to be dumb just to make me feel better.

George Jr.: What are you doing?
George Sr.: Separating the whites from the colors.
George Jr.: Whoa, that's racist.

George Jr.: So, Vietnam, like in Rambo.
Tam: Yes.
George Jr.: That's a cool movie.
Tam: Yes.
George Jr.: Are you in it?
Tam: No.

George Jr.: I think the saddest part about it is just how sad it is.

Adult Sheldon: I've fought many digital battles in my life, but none are as memorable as this first one with my Meemaw. By handing me the controller, she was telling me she believed in me. That inside my small, fragile frame beat the heart of a hero.

Adult Sheldon: Visiting Tam's house for the first time was an emotional roller coaster.
For example, it's traditional in Vietnamese homes to have gruesome religious iconography near the entrance. I did not like that.
However, it's also customary to not wear shoes around the house for sanitary reasons. I did like that.
Interestingly, one of the main ingredients in Vietnamese cooking is an extremely pungent condiment known as fish sauce. I did not like that.
But before every meal, it's common for everyone to wash their hands and face. I did like that.
Forks are not customary in a Vietnamese household. I did not like that.
And instead of napkins, there was one towel for everyone to share at the table. Seriously, what are they thinking?

George Jr.: Hey, now that you're treating him like an adult, can I have his allowance?
George Sr.: That allowance is for chores, which you already don't do.
George Jr.: Come on. We all know I'm your favorite.
Meemaw: You're not even his third favorite.

Sheldon: Do people know about this?
Meemaw: Sheldon, what's on a person's face is not always what's in their heart.
Sheldon: Well, this changes everything. How do you know who to trust?
Meemaw: You don't. That's what makes life interesting.

George Jr.: Mornin'.
Mary: Mornin'.
George Jr.: I slept in the nude last night. Felt every little breeze.
[Sheldon slides his food away]
Mary: Thank you for sharing that.
George Jr.: You're welcome.

Sheldon: How do we love our neighbors when our moms hate each other?
Billy Sparks: Who does your mom hate?
Sheldon: Your mom.
Billy Sparks: Hey, my mom hates your mom. Small world.

Billy Sparks: Hello.
Herschel Sparks: Hey.
George Sr.: Hey, Billy.
Billy Sparks: Was this fence window always here?
Herschel Sparks: No, son, that's a new fence window.
Billy Sparks: Anybody else getting dizzy?

George Jr.: Maybe you should go across the street and apologize.
George Sr.: I can't do that.
George Jr.: Why not?
George Sr.: 'Cause if I do, it sets a bad precedent.
George Jr.: What's Nixon got to do with it?
George Sr.: What?
George Jr.: You said "bad president," like Nixon. You know, this guy.

Billy Sparks: Who's Melissa?
Missy: Me.
Billy Sparks: Then who's Missy?
Missy: "Missy" is short for "Melissa." Like how "Billy" is short for "William."
Billy Sparks: I don't understand.
Missy: You know how your real name is William?
Billy Sparks: I'm Billy.
Sheldon: No, we call you Billy, but your real name is William.
Billy Sparks: But my underpants say "Billy" in them. Mom, is my name William?
Brenda Sparks: [sighs] Yeah.
Billy Sparks: Then whose underpants am I wearing?

Adult Sheldon: Ignoring things that irritate me isn't my strong suit. Obsessively fixating on them, now that's what gets me out of bed in the morning.

Adult Sheldon: My father didn't always get the credit he deserved. The advice he gave me actually worked out pretty well. Of course, I never told him.
George Sr.: Talked to Billy.
Missy: Why would you do that?
George Sr.: No, it was good.
Missy: Stay out of my life.
Adult Sheldon: He may not have been the world's greatest dad. But maybe we weren't the world's greatest kids.

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]

Meemaw: Hello?
Dr. John Sturgis: Did you know that word "hello" wasn't used as a greeting - until the invention of the telephone?
Meemaw: Hi, John.
Dr. John Sturgis: To end a phone call, it was suggested to say, "That is all."
Meemaw: Is that all, John?
Dr. John Sturgis: No, I wanted to invite you to dinner tomorrow night.
Meemaw: Great. Where we going?
Dr. John Sturgis: I can't tell you that. It's a surprise.
Meemaw: You want to give me a clue so I'll know how to dress?
Dr. John Sturgis: Well, dress as if you were going to a Mexican restaurant.
Meemaw: Oh, we're going to Puerta Roja.
Dr. John Sturgis: I can't tell you that, it would ruin the surprise.
Meemaw: John, you do realize that I'll be the one driving us there.
Dr. John Sturgis: Fine, we're going to Puerta Roja, but everything else is a surprise. That is all!

Adult Sheldon: A primary feature of quarks is that they're always bonded together, but in that moment, I felt like a neutrino, destined to be alone forever.
[Montage of young Leonard, Penny, Raj, Howard, Bernadette and Amy at that moment]
Adult Sheldon: Thankfully, I was wrong.

George Sr.: Sheldon, all you got to do is be cool.
Adult Sheldon: "Be cool." He might as well have asked me to fly around the backyard.

Adult Sheldon: Dr. Sturgis was a wise man. It was a learning opportunity. And when the day comes that I'm wrong, I fully plan to admit it.