Sarcasm Failure/Playing With

Basic Trope: A character who normally delivers sarcastic replies or irreverent one-liners is struck speechless, either by the seriousness or the sheer idiocy of the situation.
 * Straight: Tim, a detective who has been quipping to black at dead bodies the whole series, remains silent when the body is a little kid, suffocated with a teddy bear.
 * Exaggerated: Tim breaks down crying.
 * Justified: Tim is the Friend to All Children.
 * Some things cannot be joked about.
 * Inverted: The normally-humorless Ted suddenly gets in a good zinger.
 * Subverted: Tim suddenly says, "Heh, you know, I could joke about this, but it would be just too much to ... stand."
 * Double Subverted: Whereupon he starts weeping.
 * Parodied: Tim tries to get in a one-liner, only to be constantly interrupted by someone else doing it instead.
 * Deconstructed: Tim uses his sarcasm as a coping mechanism, and when he realizes that he's lost the one last barricade against the trauma to which he has been witness, he has a complete breakdown.
 * Reconstructed: After a little episode when he failed to make a quip, Tim realizes that hiding behind sarcasm isn't a healthy way of coping with his stress, and tries to learn a healthier method of dealing. That doesn't mean he won't still have a clever one-liner ready for when it's actually appropriate.
 * Zig Zagged: Sometimes Tim is speechless at particularly horrifying events, sometimes nothing escapes his wit. He just can't seem to find any consistency -- which he himself remarks upon.
 * Averted: Tim delivers a one-liner as usual.
 * Enforced: The editors ruled "Dude Not Funny" on the proposed joke, so they took it out.
 * Lampshaded: "Tim? Are you actually speechless for once?"
 * Invoked: Tim is assigned a case that the higher-ups know he won't be amused by, just to get him to quit it with the sarcasm.
 * Exploited: ???
 * Defied: Tim is mortified by the dead child, but forces himself to keep up the caustic wit to maintain his reputation.
 * Discussed: "I don't think even Tim could possibly make a joke about this."
 * Conversed: "Watch, they're gonna make it clear the audience is supposed to be mortified by having Tim not even make a joke. Just you wait, it'll happen."
 * Played For Drama: The victim is a child. Tim doesn't joke because the situation is too tragic.
 * Played For Laughs: The victim turns out be a grown man who's died in a bizarre S&M accident involving the insertion of a cucumber too far up an orifice whole cucumbers normally should not be inserted. Tim tries to get a joke off the ground but fails because the situation is too crazy even for him.

Not going back to Sarcasm Failure is a fantastic idea!

Oh... Oh my...