The Communication Deterioration

The Big Bang Theory 8×21

& Leonard: When I encountered alien life, I-I discovered that the key thing was not to sit in its spot.
    Sheldon: All right, you can’t breathe our air without an inhaler, he’s allergic to Earth nuts, but I’m the alien.

& Penny: Sheldon. Sheldon. Sheldon.
    Sheldon: .... I bet that started off as a joke, but by the third one you realized there was something strangely enjoyable about it.
    Penny: Yeah, I kind of want to do it again.
    Sheldon: I don’t recommend it. You’ll be doing it the rest of your life.

& Sheldon: Hmm. I know exactly what you should do. Unfortunately, I cannot tell you.

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& Penny: You’re right. I’m worried about something that hasn’t even happened yet. Huh. You are a wise man.
    Sheldon: Well, Penny, who’s smarter: the wise man or the person who comes to him for advice?..
    Penny: Oh, I guess you’re right. Maybe it is the person who asks.
    Sheldon: No, it’s the wise man. That’s why he’s called the wise man. You know how I know that? I’m the wise man.

& Leonard: Animals do deliver messages through scent.
    Raj: Bees talk to each other by dancing. Whales have their songs.
    Leonard: Penny has about 20 different ways of rolling her eyes that each mean something different...

& Penny: The whole experience reminded me about how much I hated about that world. You-you know, the anxiety, the depression, the negativity. I don’t want to feel those things. I want to sell drugs to people who feel those things.

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On the IMDb