There is SO much that suggests it. That's what got me at first, i always thought it was a straight forward story. For instance, think over the lyrics of the Candy Coloured Clown song when Frank sings it to Jeffrey. It's all about Freudian impulses in the subconscious, the Oedipal complex, voyeurism. Jeffrey's real story starts when he goes into the closet and ends when he leaves it, the mix of surrealism throughout, the doubles. That's why i love this film so much, there's so much in it that Lynch doesn't draw attention to like his later films, imo it's far more intelligent in that it can be both these films. It ties into the theme of surfaces throughout the film, on the surface it's a simple story but underneath there's a lot more, like the underbelly of the society.
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I was recently in an independent comedy-drama about post-high school indecision. It's called Generation Why.
See the trailer here: