Leonard: Thankfully, Penny and I have a relationship built around honesty.
*Amy and Bernadette chuckle*
Leonard: What? I don't lie to her.
Bernadette: Oh, we know you don't lie to her.

Howard: I'm sorry I didn't take you to the airport. I just want you to know I'll never forgive myself for being so selfish. And I promise to keep you close for the rest of my life.
Bernadette: Oh, no, that thing's gonna end up in my bedroom.

Bernadette: You better find my husband's mother, 'cause one way or another we're walking out of this airport with a dead woman.

Bernadette: Gosh, Amy. I'm sensing a little hostility. Is it maybe because like Sheldon's work, your sex life is also theoretical?

Penny: Sheldon, what did we say about being a nicer friend?
Leonard: Thank you.
Penny: Leonard, what did we say about being a gullible weeny?

Raj: Hey, listen to this. Murder, cannibalism and satanic rituals are just a few of the thousand-plus horrors that await.
Howard: I just helped my mum out of the tub, so I'm one slippery horror ahead of you.

Raj: You know when Cinnamon won't take her medicine. I hide it in a piece of cheese.
Howard: Good idea. We can wrap up the pill in cheese, feed it to Cinnamon and then my mom can eat Cinnamon.