Any time Lwaxana freaks Odo out.
Dax pranking Odo by moving things in his quarters.
Worf saying "I am NOT a merry man!"
Worf in the baseball ep of DS9 saying "Death to the opposition!" and "Find him and kill him!"
When Odo tells Worf he's talking to a Changeling, not a beverage, and Worf looks at his own drink as Odo walks away.
The tribbles raining down on Kirk!
Spock saying "One damn minute."
Spock mind melding with whales.
Spock nerve pinching the asshole with the boombox is gold.
Shakaar and O'Brien trying to pull on Kira when she tells them it's time to have Kirayoshi.