Brilliant CSI's? I think not.

What's up with every location in every episode of CSI taking place in the dark? The CSI geniuses are smart enough to find a kidnapped person from a single clue of a wasp larva burnt to a crisp found in the wheel well of an abandoned car, but they're not smart enough to turn on the lights in their lab to examine evidence? The biggest item in the crime unit's budget must be for flashlight batteries. Gimme a break.