6th Sense
Inglourious Basterds
"They were spies pretending to be Germans. Europeans (or Germans at least) make a three with their thumb instead of their ring finger, thus giving away that they were not German"
The Princess Bride
"You're Gonna Need A Bigger Boat". Jaws (1975)
"Hank Realizes Who Heisenberg Is, Breaking Bad"
Game Of Thrones
"Lady Catelyn Stark realizes what's about to happen in the Red Wedding Scene."
"They're Digging In The Wrong Place"
The Usual Suspects
"Agent Kujan realizes that Keaton is the real Keyser Söze and killed the team."
Star Wars
"Luke Skywalker realizes Darth Vader is his father."
"When Clarice Sees The Moth In Buffalo Bill's House"
"When Jigsaw Gets Up From The Floor At The End Of The First Saw Movie. He Was In The Room With Them The Entire Time Playing Dead"
"House Realizes He Has Been Hallucinating"
"When Mills Realizes His Wife's Head Is In The Box! The Whole Expression Change Is Just Phenomenal"
"Wizard Of Oz: Dorothy Pulls Back The Curtain"
"The Wizard created a powerful illusion of himself to demonstrate control until Dorothy pulls back the curtain to find a small man, with microphone."
"The Silence Of The Lambs. The Moment Agent Starling Realises... It's Him!!"
"The Green Mile! When He Sees The Truth"
"When He Doesn’t See Anyone In The Room, Goodfellas"
The Professional
"As Léon dies, he presses a grenade pin in Stansfield's palm, saying that it is from Mathilda. Stansfield opens Léon's vest to find a cluster of grenades, which detonate, killing Stansfield."
The Boy In The Striped Pajamas
Die Hard With A Vengeance Elevator Scene
"John McClane realizes the officers are fake."
Shutter Movie Ending
"At the end Ben realizes that Megumi is still attached to him."
"Speed, When Harry Realizes The House Is Rigged To Blow And It’s Too Late To Get Out"
Sicario
"Fausto: "Your wife... you think she'd be... proud of what you've become?"
... Tense silence ...
Alejandro: Don't forget about my daughter...
CUT TO: Fausto's wife bowing her head as she realizes there's no talking Alejandro down."
Bridge On The River Kwai: “What Have I Done?”
It's the moment "Kujan realizes Verbal fabricated his entire story, improvising on the spot by piecing together details from random items in Rabin's cluttered office." (Wikipedia)
"I think you know."