Coming up with good dark secrets is hard sometimes. If that is the case for you, the following alternative might be interesting for you:

During character creation, you will be required to select a virtue and a vice. These should be single-word attributes (refer to the examples below), followed by a brief description of how these qualities are expressed in your character. If your virtue or vice becomes relevant in a scene and leads to detrimental consequences for you or other characters involved, you will be awarded one experience point at the end of the session.

Example Virtues: Honest, Conscientious, Pure, Modest, Serene, Patient, Industrious, Benevolent, Devoted, Compassionate, Optimistic.

Example Vices: Addictive, Arrogant, Greedy, Lustful, Wrathful, Hedonistic, Lazy, Envious, Jealous.