Two, Natalia Boa Vista

Natalia: I'm late!
Eric: For what?!
Natalia: I'm late!
Eric: What we gonna do?
Natalia: [laughs]
Eric: WHAT?
Natalia: It's just nice. You said 'we'.
Eric: It takes two to tango.

- CSI: Miami, Skeletons (4.15)

Cooperation, Western Proverb

It takes two to tango.

- Western Proverb

A common idiomatic expression which suggests something in which more than one person or other entity are paired in an inextricably-related and active manner, occasionally with negative connotations.

The phrase originated in a song, Takes Two to Tango, which was written and composed in 1952 by Al Hoffman and Dick Manning. The lyrics and melody were popularized by singer Pearl Bailey's 1952 recording.

http://en.wikipedia.org/wiki/Takes_two_to_tango_(idiom)