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 reason the drug smuggler from Chungking Express's first half is always wearing the trench coat and sunglasses is that the actress was working on another movie simultaneously, and because of Chungking Express's tight schedule they decided to just cover her up instead of bothering to remove her makeup.