...or just one shot or line of dialogue? A historical error? A painfully obvious bluescreen closeup that is probably post-production (normally involving someone in a car)? An overlong sentimental manipulator? A scene that doesn't know when to end? I'm not talking bloopers.
LOTR notwithstanding, there are a few for me off the top of my head:
The family reunion scene at the end of Spielberg's War Of The Worlds.
"Is it raining? I hadn't noticed." in Four Weddings And A Funeral.
The dog jumping out of the way of the fireball in Independence Day. Oh, and the President's "rousing the troops" speech near the end.
The bluescreen at the end of The Hunt For Red October.
The fight scenes in Thunderball which are obviously sped up.