- Sheldon Cooper: I had a song stuck in my head, and then I realized the song was about you. And just like an earworm, I can't get you out of my heart. What I'm trying to say is, you're my heartworm. The metaphorical kind, not the poodle-killing kind.
- Sheldon Cooper: I have an eidetic memory, I should be able to remember what this song is. Something must be wrong with me.
- Penny Hofstadter: See? I told you if we waited long enough he'd figure it out.
- Sheldon Cooper: This song won't get out of my head! Can you imagine anything so irritating?
- Leonard Hofstadter: This is a trick question, right?
- Bernadette Rostenkowski: You're letting a man into your room. That's intimate. It's where your panties live.
- Sheldon Cooper: This is the beginning of my descent into madness. Soon I will test the limits of public nudity.
- Penny Hofstadter: Public nudity?
- Leonard Hofstadter: Don't worry, it just means going barefoot.
- Penny Hofstadter: Do you even like the Beach Boys?
- Sheldon Cooper: They have beach right in their name. What do you think?
- [Opening lines]
- Sheldon Cooper: Sheldon Cooper's Descent into Madness, Day Two. It's 2:25 and I feel the need to urinate. My usual urination time is 7:30. Yet here I am, struggling to keep my mind sharp, and my pajamas dry. Soon I will lose my tenuous grasp on reality. I guess I should go pee while I still know what a toilet is.
- Amy Farrah Fowler: That's an interesting tie clip.
- Dave Gibbs: Oh thanks. It's Avogadro's constant. It's useful for calculating the number of atoms in a substance or causing regret in anyone who asks about it.
- Leonard Hofstadter: Since when do you hum songs?
- Sheldon Cooper: What are you talking about?
- Leonard Hofstadter: You were just humming.
- Sheldon Cooper: Are you sure? Sometimes when my brain really gets moving, it makes noise.
- Penny Hofstadter: She did soften your life, didn't she?
- Sheldon Cooper: Yes. She's like the dryer sheets of my heart.
- Sheldon Cooper: Dear crazy future Sheldon, this is a thermostat. It controls the temperature of the apartment. The ideal setting is 72 degrees. If you find this too cold, then put on a jacket... a straight jacket, 'cause 72's the best and you're crazy.
- Sheldon Cooper: Empedocles thought he was a god and jumped into a volcano. Pythagoras had an irrational fear of beans. Tesla fell madly in love with a pigeon, who he claimed loved him back.
- Penny Hofstadter: Maybe he just had bread in his pocket.