Dark secret is a one point flaw :

You have some sort of secret that, if uncovered, would be of immense embarrassment to you and would make you a pariah in the Kindred community. This can be anything from having murdered an elder to having once been a member of the Sabbat. While this secret weighs on your mind at all times, it will only surface in occasional stories. Otherwise, it will being to lose its impact.

What's the darkest/funniest/strangest secret you've had ?

Here's mine : In the city of Paris where Francois Villon is the Toreador Prince, my character...