I had never heard of the Manic Pixie Dream Girl trope in film. It is really quite insidious.
For me, it was Julie Christie in Fahrenheit 451 (1966). My ideal had long blond hair, wore a peasant dress and walked bare foot around the streets of San Francisco in 1967 – the Summer of Love. I got over it fairly soon because 1968 was such a abominable year.
However, it was great to see Christie in the Canadian film Away From Her – what a glorious, complex character.