Sometimes it’s Kaylee reassuring Mal with, “Everything’s shiny!”
Sometimes it’s River telling someone, “I can kill you with my brain.”
Sometimes it’s the assertion that the crew are “Big damn heroes,” or that they, “Aim to misbehave.”
And sometimes it’s a spiritual counsellor telling a crew ember that there’s “A special kind of hell” waiting for people like the.
Whatever the occasion, there’s a line that comes tumbling out of the characters’ mouths that will, at some point, be exactly the right thing to say in real life.
This is the case with pretty much everything in which Joss Whedon is involved, but I think it’s particularly true of Firefly.