Sleepiness is weakness of character. Ask anyone.

Wash: Don’t fall asleep now. Sleepiness is weakness of character, ask anyone.
Zoe: It is not!
Wash: You’re acting Captain. You know what happens, you fall asleep?
Zoe: Jayne slits my throat and takes over?
Wash: That’s right.
Zoe: And we can’t stop it?
Wash: I wash my hands of it. Hopeless case. I’ll read a nice poem at the funeral. Something with imagery.
Zoe: You could lock the door. Keep the power-hungry maniac at bay.
Wash: Don’t know. I’m starting to like this poetry thing. “Here lies my beloved Zoe, my autumn flower… somewhat less attractive now that she’s all corpsified and gross—”