Context

This line is spoken by Hudson, played by Bill Paxton, in the film Aliens, directed by James Cameron (1979).

When the going gets tough—like, say, you're stranded on an alien planet and you're facing sudden death—you can either hold it together like Sigourney Weaver, or you can lose your cool and start shouting helplessly like Bill Paxton, one of James Cameron's favorite actors, in 1986's Aliens. 

Where you've heard it

You'll hear this one on internet message boards—when all seems lost (like someone didn't get an iPhone on launch day, or they did get one and then immediately dropped it in the toilet)—expressed via this meme. Or this one.

Additional Notable References

• A T-shirt
• Left 4 Dead, video game
• Mystery Science Theater 3000

Pretentious Factor

If you were to drop this quote at a dinner party, would you get an in-unison "awww" or would everyone roll their eyes and never invite you back? Here it is, on a scale of 1-10.

Not pretentious; just cowardly. Don't be like Bill Paxton. Be like Sigourney Weaver. Always.