Sheldon: Mother?
Mary: Yes?
Sheldon: Is it okay if I use a knife to butter my toast, or are you worried I'll do something crazy with it?
Mary: You can butter your own toast.
Sheldon: Oh, good. You see the toast, too. I was afraid I was imagining it.

Missy: What's it like to not believe in God?
Sheldon: It's great. Big fan.
Missy: Are you ever afraid you're wrong?
Sheldon: About religion? Never. About other things? Also never.

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: Let's say grace.
Sheldon: Hang on, safety first. [puts mittens on]
George Jr.: When are you gonna get over that?
Sheldon: I would think recent events would make you value protection.
Mary: Enough.

Mary: I was just letting you know that if you were having any problems you could come to me with them.
Sheldon: You think I have mental problems?
Mary: Well, not problems. I'm just worried about your future, and when I see you moving subatomic particles around in the air, that makes-
Sheldon: Subatomic particles are real! You talk to an invisible man in the sky who grants wishes. If anyone's mental, it's you.

Sheldon: [to Mary] I am behaving no differently than I ever have. Why are you suddenly so worried about me?
Dr. Goetsch: That is a valid question. Has anything changed recently?
Sheldon: Maybe it's hormonal. When does menopause typically begin?
Mary: It is not my hormones.
Sheldon: Well, it certainly isn't mine. I'm showing no signs of puberty.

Mary: Shelly? Shelly? Everything okay?
Sheldon: [nasally voice] Hunky-dory. Why?
Mary: Well, you're kind of dressed like you kidnapped yourself.
Sheldon: Oh, I'm trying to block out sensory input. I hit a roadblock determining whether virtual particles have a fixed mass or violate momentum conservation. But then I remembered that Nikola Tesla believed that isolation is where ideas are born.
Mary: Who's Nikola Tesla?
Sheldon: One of the most prolific scientists of the 20th century.
Mary: Okay. And, um just out of curiosity, how isolated was he?
Sheldon: Oh, highly. He found human contact revolting.
Mary: [sigh] Well, that's kind of a lonely way to live, don't you think?
Sheldon: Well, he wasn't entirely alone. At the end of his life, he became good friends with a brown pigeon.