Who's Blake Snyder? He wrote Save The Cat, which is the latest in a series of "must-read" books about screenwriting. If you take a screenwriting class anywhere in Academia, the name "Blake Snyder" will pop up.
Blake Snyder says something must happen on page 25. Must. He says whenever someone hands him a script, the first place he goes is, you guessed it. But don't take my word for it. Let's go straight to Blake himself:
Wise words, succinctly put.
He died a couple months back. All of us who read his books will miss him.