I... was planning on reading all of your secrets without adding anything of my own!!! Bow before my superior darkness you poor, misguided fools!
OT: I have some... Depending on what you consider to be dark, I guess. I have ones that I'm embarassed of (like, say, fetishes) but nothing that I can think of that's like what I'd consider blackmail material.
But, here's a couple. First, I guess I'm kinda manipulative. Not in an overly-controlling-evil-puppet-master-with-all-you-fools-dancing-on-my-strings kind of way, but when I want something to happen or people to do something, I'll do my damn well best to make sure they think it's their idea. I can't trace the reason behind this beyond the simple fact that, for whatever reason, I'm terrified of letting people know what I want. I guess I'm scared of revealing that much of myself and being reviled, so I'll take any route possible to put the idea in their heads so they'll bring it up first and tell me their opinion of it. That way, I can safely tell them as much as I feel is appropriate without revealing such that they might have a negative reaction to it.
Another is not such a secret among my closest friends, but something that's quite a sensitive spot for me; I can't write a novel. I've been trying literally since I was in primary school, and my greatest dream is to write a famous fantasy epic, but no matter how hard I try, I'll come up with a new idea, write a few pages, completely lose interest and abandon it. It's the bane of my aspirations, and perhaps the one part of myself that I TRULY dislike (for the rest of me self-esteem-wise I've sorta come to accept that I am as I am, so I might as well get used to it).