Mary Cooper: You know, you two make a cute couple.
Leonard: No, no we're not, we're not a couple, we're single, two singles, like those individually wrapped slices of cheese that are friends.
Mary Cooper: Did I pluck a nerve there?
Howard: Oh yeah.

Leonard: What ya doin' there? Working on a new plan to catch the Road Runner?

Penny: Why can't all guys be like you?
Leonard: Because if all guys were like me the human race couldn't survive.

Leonard: So if you are considering going into experimental physics, my door is always open. Once again, I'm sorry that the demonstration didn't quite work out. But now we know what happens when you accidentally spill peach snapple into a helium-neon laser. The short answer is don't.

Leonard: Oh, I forgot about this (sweater). My aunt made it for me when I finished college.
Penny: Aww, did she hate you?
Leonard: Why because I got an ugly, itchy sweater and my brother got a car? No, I was her favorite!

Officiant: Is that the song from Toy Story?
Penny: He loves that movie.
Leonard: (emotional) I do.

Leonard: Ooh, flowers and chocolates? Somebody's trying to get me out of my panties.

Penny: Can you please go talk to him?
Leonard: Come on, I take care of him all day long. You do it for once.
Penny: Once? Who got the gum out of his hair?
Leonard: What do you want, a medal? It was your gum.

Sheldon: This place is terrific. Why have we never been here before?
Leonard: The same reason we don't do a lot of fun stuff - you.

Penny: Thanks for cooking.
Leonard: My pleasure.
Penny: That carrot was delicious.
Leonard: Yeah. I wish I'd fought harder for the rest of 'em.

Raj: Leonard, give me a beat.
Leonard: I will not.

Dave: OMG! Aren't you Leonard Hofstadter?
Leonard: Yeah.
Dave: I saw you speak at Stanford with Sheldon Cooper! Amy, can you believe it? It's Dr. Leonard Hofstadter!
Amy: No. Pinch me.
Dave: It's an absolute pleasure to meet you. Can I shake your hand?
Leonard: I don't know if you want to do that, I was just-
Okay, never mind.
Dave: Amy, I'm never washing this hand again.
Leonard: You really should.

Penny: Aw, jewelry. Oh my God, Lakers tickets!
Leonard: It gets better. Instead of me you can take someone who will actually enjoy it.
Penny: You are the best boyfriend ever.
Leonard: Seriously, please don't make me go.

Howard: Lots of people wear matching pajamas who aren't dating.
Raj: Like who?
Howard: Like you and your dog.
Leonard: Don't rule out the dating.

Sheldon: Well, they were no help at all.
Leonard: Which is crazy, since rock and roll is all about good customer service.