Headcanon
1) She does not believe in ghosts, or most things that you can't see or touch physically. It's why she can believe in such as thing as Persona, Shadows and even a God due to the fact she has seen and touched them, so she knows there isn't a way to disprove it, but ghosts you can't touch, so there not really there. That's how Naoto's logic on it works basically.
2) While it's true that she spent most of her childhood reading the many detective novels, she rather enjoyed attempting to make gizmo's that were actually based in the books she read, although she failed in actually making them work and most than not she broke them. The only successful things she did make were things not based on any book.
3) Apart of the reason Naoto works a little to hard is not because she's a perfectionist, but because she wants to prove herself if the eyes of the police who call her a child. She hopes that by cracking something for them, that they would see her more as a the Detective that she is, rather than a child because of her age. Although the perfectionist thing is more for if something doesn't seem right to her, then she can go a little overboard.
2) While it's true that she spent most of her childhood reading the many detective novels, she rather enjoyed attempting to make gizmo's that were actually based in the books she read, although she failed in actually making them work and most than not she broke them. The only successful things she did make were things not based on any book.
3) Apart of the reason Naoto works a little to hard is not because she's a perfectionist, but because she wants to prove herself if the eyes of the police who call her a child. She hopes that by cracking something for them, that they would see her more as a the Detective that she is, rather than a child because of her age. Although the perfectionist thing is more for if something doesn't seem right to her, then she can go a little overboard.