A REALLY good movie is one you can watch over and over again - spotting something new in it each time.
But sometimes the little details are so well hidden you might never spot them, even after a lifetime of re-watches.
Here is an incredible list of such 'blink-and-you-miss-em' movie moments that you won't believe you've never seen them before.
And now you do, they are likely to change the way you watch your favourite flicks forever.
Even classic movies like Back To The Future, Home Alone and The Matrix.
So enjoy this list of movie Easter eggs - how many had YOU seen before?
1. Harry Potter - Cereal thriller
What's your favourite spell in Harry Potter?
2. Home Alone - Barking mad
3. Batman Returns - Curious...
Michelle Pfeiffer as Catwoman licks Michael Keaton's face in Batman Returns 4. Star Trek - Kirk runs a dry ship
New Star Trek Into darkness trailer warps in 5. Up - Can't stop progress
7. Shaun of the Dead - Dead clever
8. The Matrix - Camera tricks
Extended Matrix trailer Starring Keanu Reeves and Laurence Fishburne 9. Spider-Man 2 - Car-azy
10. Interstellar - Not too corny
Interstellar: Final trailer for Christopher Nolan space epic 11. The Princess Bride - Inconceivable!
30th Anniversary trailer released for The Princess Bride with Cary Elwes, Robin Wright and Chris Sarandon 12. Harry Potter - Darkness dawning
Trailer for the very first film in the Harry Potter film franchise 13. Fight Club - Always read the small print
14. Pulp Fiction/Kill Bill - When worlds collide
15. Back To The Future - Get the point?
Back to the future 1985 trailer starring Michael J. Fox and Christopher Lloyd