E.T. the Extra-Terrestrial
What makes this film such a timeless classic is the emotion that runs throughout, and that final heartbreaking scene when E.T. leaves.
Spielberg, the master of shaping our childhoods, figured he’d get the greatest payoff from the young actors in the finale, if he shot the last goodbye scene on the last day of filming. The kids were legitimately emotional because they knew that they’d be saying goodbye to everyone on set later.
That sounds like an evil genius at work.