In the most recent episodes of the Battlestar Galactica re-imagining, we have four rather major characters who discover, or at least have a strong reason to believe, that they are Cylons. That is, they are indeed their own worse enemy.
The beauty of this is that there is no active betrayal, no sudden change, or no sure way of knowing for certain that it is the case. You simply are.
I find this intriguing, this instant conversion of everything you are and you believe in. Suddenly you are a spy on your own psyche, watching and noting anything that could be considered out of the ordinary, at least as you define it. You become the stranger, desperately seeking a measure of proof to know who you truly are one way or the other.
What a powerful psychological weapon this becomes at the disposal of the Cylons. All you need to place the weapon into action is to plant the seed of doubt. In this case, all it took was music that no one else could hear, simple music that did not fit into the normal realm of accepted perception. This could be extended to practically anything that could be weighed by our mind's judgment, such as visions, smells, even subtle shifts in attitude. A bad day could truly turn into self-inflicted disaster.
This is probably one of the better mechanisms of attack found in Science Fiction, and while it has been explored before this is a fine example of playing it out on a grand scale. What better than to turn the enemy on themselves, and in this case the turmoil is carried down to the individual as they begin to doubt their own purpose.
Imagine the feeling the characters would have when looking in the mirror, wondering whose eyes are looking back at them. Then again, given all that we know that the human race is capable of, seeing a Cylon looking back at you might not be one of the worse things. That is, if you don't mind religion seeking murderous robotic races as a general rule of thumb.
Aloha from the Beach,
greg