Why do we have more negative feedback than positive feedback?

Because you tagged this question with "body", I think you are going for something different than what the previous answerers gave you.

Negative and positive feedback loops, when referring to hormones in the body, refer to decreased or increased production of something, usually a hormone, in response to some stimulus from inside or outside the body. There are more negative ones than positive, because usually the stimulus makes us perform an action that decreases the response to the stimulus. The overall goal is to maintain homeostasis--a constant internal environment. For example, an increase in blood pressure is sensed by sensors in the blood vessel walls. This is relayed to the brain, which sends appropriate messages to decrease heart rate.