I really like the Alex Benedict ("Etude in Black") quote: "I think there's a possibility, but I don't think it's distinct." I'd like to use that in some kind of debate/argument, perhaps. Also, the Oliver Brandt quote in "Bye Bye etc": "The world's crumbling, what do you expect?" That could be a stock response to anyone bemoaning the state of our culture. Or, to anyone who asks, "What's going down?", Joe Develin's ("The Conspirators") brilliant response: "The world, in terminal descent."

Mine that I'm (still) waiting to use is the one from "Murder Under Glass," opening scene:

"He can never say he allows himself to be blinded by good taste."

Then there are ones that ONLY a fan would be likely to get. Sometimes when I hear someone jumping to conclusions I feel like saying "Cigar ashes!" (After Milo Janus.)