Sheldon: Maxwell's equation my sweet patootie!

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.

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.

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.

Ms. Hutchins: Sheldon, why aren't you in second period?
Sheldon: I'm working on this math problem.
Ms. Hutchins: I think you might be the first person in history who's ever cut class to do math.
Sheldon: The irony wasn't lost on me.

Sheldon: Thank you for asking. I appreciate it. And how are you doing?
Ms. Hutchins: Since when are you interested?
Sheldon: My father told me I should be kind to old people.
Ms. Hutchins: How old do you think I am?
Sheldon: My father also told me if a woman ever asks you that, it's a trap.
Ms. Hutchins: Smart man.
Sheldon: But I'll say 53.