I watched The Last Unicorn so much the tape died a slow and painful death. The household VHS of MLP survived a lot longer but I'm pretty sure that everyone else in the house wished it would die.
Honorable mentions: Goonies(1985), ย The Neverending Story(1984), Puss In Boots(1988), Labyrinth(1986), Red Riding Hood(1987), and The Dark Crystal(1982).
