Adult Sheldon: In the world of collecting, I'm what's known as a completist. For example, I own every gauge of model train from the mighty "G," to the tiny "T." Look at how cute it is, I just want to eat it up. However, the downside of being a completist is when something's missing, it's like an itch you can't scratch, even if you own a complete set of Justice League back scratchers... which I do. In this case that itch was the comic book issue Doom Patrol and Suicide Squad Special #1.

Adult Sheldon: The next day, as I walked across campus, I could feel all eyes were on me, judging me for my failure. Look at them laughing at me. It was the closest I ever came to a walk of shame.

Adult Sheldon: This marked the beginning of what our family would come to call "Missy's difficult period." Despite my repeated assurances that I could solve the problem with a brain scan and some low-voltage electric shocks, I was never given the opportunity. Such a shame.

George: Well, what does he know? He's just a dumb teenager.
Mary: [sighs] I guess it is normal for teenagers to blame their parents for stuff.
George: Sheldon's normal. That's a shocker.
Mary: Great, the one normal thing he does is blame me.
George: [chuckles] Someday his kids are gonna tell him he's ruinin' their lives.
Mary: You think?
George: If he has 'em, they're gonna say it. So probably not.
Adult Sheldon: Joke's on him. I did have kids. And joke's on me. They say it all the time.

Sheldon: Are you sure there's a body down here?
Missy: Oh, yeah, keep digging.
Adult Sheldon: I'd like to tell you I found something that night, but for once you all might be ahead of me.

[future:]
Amy Farrah Fowler: And since when do you go out of your way to make other people happy?
Adult Sheldon: How about once a year on your birthday?
Amy Farrah Fowler: Other than that, when?
Adult Sheldon: All the time.
Amy Farrah Fowler: Sheldon, while I was giving birth, you Zoomed in to a seminar.
Adult Sheldon: You were taking forever to dilate, and I had already made my contribution to the project. Which, need I remind you, was on your birthday.

[future:]
Amy Farrah Fowler: Oh, my.
Adult Sheldon: What are you doing?
Amy Farrah Fowler: You never told me you were baptized.
Adult Sheldon: Yes. And I got a pretty nasty ear infection for my troubles.
Amy Farrah Fowler: And you went through with it just to please your mother.
Adult Sheldon: Well... she may not have understood me or the things I cared about... [sighs] but she did everything she could for me. My dad did, too. [Sheldon looks a photograph on his desk of his younger self and George]
Amy Farrah Fowler: Hmm. That must've been great, having parents who supported you despite all your differences.
Adult Sheldon: Oh. Yes. Looking back, that was... that was the ultimate gift.

[future:]
Amy Farrah Fowler: Hey. Smartest man in the world. I brought you to the water. Take a freakin' sip.
Adult Sheldon: You're drawing a parallel.
Amy Farrah Fowler: Yes.
Adult Sheldon: I'm not wearing the jersey.
Amy Farrah Fowler: Okay. But it is cold there.
Adult Sheldon: Fine. I'll wear it.
Amy Farrah Fowler: And, by the way, your daughter wants to take acting classes.
Adult Sheldon: I told you we never should've let Penny babysit.

Adult Sheldon: It was family dinners like this that led me to adopt a mid-Atlantic accent. Nobel Prize winners [in a Southern accent] ought not be orderin' tater tots.

Adult Sheldon: And what about Count Chocula? How is he a count? Did the title come with land?

Adult Sheldon: Of all the afflictions that can befall a child, one reigns supreme. Beyond scraped knees and paper cuts, nothing strikes fear into the hearts of kids around the world like a splinter.

Billy Sparks: You can cheat off me if you want. I studied.
Missy: [whispers] Thanks.
Adult Sheldon: I'm not saying it was God or zero, but a small miracle did happen that day. Billy passed the test with a 68 and went on to the seventh grade. Where he remained for the next several years.

Adult Sheldon: I wasn't always as emotionally intelligent as I am today. For example, when my father died, I was flummoxed by all the different ways people expressed grief. My mother threw herself into religion. My meemaw turned to a different kind of spirit. My brother tried to fill the vacuum created by my father's passing.
Georgie: $3,500? You do realize we're talking about the beloved head coach of a winning football team? There's an argument...
Adult Sheldon: And then there's all the friends and neighbors who expressed their grief with food.
[montage:]
Brenda Sparks: I made you a casserole.
June: I made you a casserole.
Audrey: I made you a casserole.
Peg: I bought you a casserole.

Adult Sheldon: And of course, I thought about Star Trek II: The Wrath of Khan...
Spock: I have been, and always shall be, your friend.
Adult Sheldon: ...and how upset I was over the death of Spock.
Spock: Live long... and prosper.
Missy: What are you doing?
Sheldon: Thinking about Star Trek.
Missy: What is wrong with you? Our dad just died.
Adult Sheldon: And some people express their grief by lashing out.

Adult Sheldon: I don't care how dimwitted you are, scientific principles have to make you smile. Of course, nobody I knew in East Texas in 1989 cared about Newtonian physics. The only Newtons they cared about were Wayne and Fig.