What is the importance of this quotation

Goldberg: Why don’t you pay the rent?

McCann: Mother defiler!

Goldberg: Why did you pick your nose?

McCann: I demand justice!

Goldberg: What’s your trade?

McCann: What about Ireland?

Goldberg: What’s your trade?

Stanley: I play the piano.

Goldberg: How many fingers do you use?

Stanley: No hands! ...

Goldberg: Speak up, Webber. Why did the chicken cross the road?

What is the importance of this quotation?