*Leonard using his inhaler*
Penny: I told you not to do the worm.
Leonard: (out of breath) You were right.

Leonard: What would you be if you were attached to another object by an inclined plane, wrapped helically around an axis?
Sheldon: Screwed?
Leonard: There you go.

Sheldon: This song is never going to stop. Have you ever dealt with something so relentlessly irritating?
Leonard: That's a trick question, right?

Leonard: Penny, as a scientist, my job is to figure out why things happen. But I don't think I'll ever understand how someone like me could get to be with someone like you. You know maybe I don't need to understand it, I just need to be grateful. I love you, Penny.

Penny: We wouldn't even sit in your spot while you're gone.
Sheldon: You're darn right, you wouldn't. No matter where I am, this will always be my spot. Like an embassy in a foreign country, this seat is the sovereign soil of my bottom.

Penny: The new neighbors are weird.

Penny: Do they know why the pipes burst?
Amy: They didn't say.
Leonard: Buildings that have a combination of copper and galvanized steel are susceptible to pinholes and corrosion caused by the mobility of ions in the water. Can't have your head shoved in a toilet as much as I did and not pick up a few things about plumbing.