Me: Johnny Quest. It used to scare the life out of me, and I'd be unable to sleep. A year or so ago I looked up one episode which particularly terrified me on youtube, and I felt embarrassed for the producers and voice actors at how bad it was. Really, really, jaw-droppingly bad, flat dialogue and effects so terrible it took mental strain to work out what they were supposed to be. No idea why it used to freak me out.
Also: spinach. I used to devour it, along with brussel sprouts and broccoli, when I was a kid, because my brother would steal my food and only left the things he didn't like, so I had no choice but to love the stuff. Now that I'm older and can choose what I eat, I've found that I don't actually like the taste, and it was probably mostly self-delusion.
My husband: Wonder Woman. He watched TV episodes when he was 5 or 6, and thought they were really cool and amazing and lifelike. He also watched some recently and is ashamed that he ever thought it was real. Again, very bad special effects and acting. Kind of like Xena: Warrior Princess on a budget one-tenth the size.