Star Trek: The Next Generation - Riker's Finger Gesture
After chasing an errant torpedo in a shuttlecraft, Picard and Data return to the ship to find everyone has de-evolved. They walk into the Captain's Ready Room and find caveman Riker trying to break through the fishtank. When Riker sees them, he sneers. One hand still on the tank, he slowly brings it down curled, but with the middle finger raised. As if he were making a comment to someone off-screen. Camera cut back to Picard, who looked shocked.