There are a lot of examples I could list, but the biggest for me is The Neverending Story. I watched it a few years ago with a friend (who also loved it as a child) and by the end we were both stunned by how bad it is. The story is so bare-bones, it's like somebody looked at a fantasy plot outline and stretched it into a whole movie without actually filling in any of the blanks. It moves so fast that nothing has any substance. "Because reasons" is usually the only explanation we're given for the rules of the world or any action a character takes.
To this day, my friend and I still out-of-the-blue ask each other, "Remember when Neverending Story ruined our childhood?"
To this day, my friend and I still out-of-the-blue ask each other, "Remember when Neverending Story ruined our childhood?"