Kill a Joke

Has someone you didn't like ever made a joke you wanted to ruin? Here is how to do it.

Steps

Pay close attention to the joke. Try not to get distracted by anything else.
Make random remarks and outbursts, such as "Wait, I think I've heard this joke before somewhere".
Right before the person gets to the end, start laughing really loudly. Try not to make it too early, or you will look like a complete idiot. If you do it too late, it will seem like you are laughing with everyone else.
If the person telling the joke says "This is so funny" before they start telling the joke, then halfway through the joke, start laughing hysterically, and say " Oh, that is funny!" It annoys people terribly.
If it is a knock knock joke, do not reply to "knock knock" with "who's there" instead reply with one of the following: "Come in" "what" "how did you find my house" "no"
Use over-estimation to deflate the joke or story. If it goes something like "Guess how much I paid for these shoes!", respond with wild over-estimation to kill it dead. For example:
- "Guess how much I paid for these shoes!"
- "I dunno... like £800?"
- "Well... no. £150."
- "Wow, yeah that's a lot." (Said with little enthusiasm.)
- The high point has been swatted effectively and all enthusiasm has been successfully removed.

Stare at them, at the end, motionless....
If you fail to laugh before the person finishes, try laughing far too long. Exaggerate and annoy.
It helps if you have know the particular joke, or have heard one similar to it.
Apply literalism. Instead of laughing, point out every exaggeration and scientific inaccuracy of the joke.
If you don't want to offend whoever's telling the joke, try to defuse it, rather than provoking it.