I'll start.
Did you know that Wil "Wesley Crusher" Wheaton's first credited acting role was Martin on the Secret of NIMH animated film? That was probably the last time he sounded assertive and tough in an acting role too, and he was both a little kid and a mouse. :rat-salute:
The trailer for Cast Away gave away that Tom Hanks made it back after being stuck on the island. This was done intentionally and Zemekis himself said something to the effect of "people want to know what happens in a movie before they go see it".
That's a great example of the difference between the two directors.