Extremes kill. 

We need fitness, not over exertion to the point if injury or death. 

We need water, not too much that we drown. 

We need food, not too much that we get and stay fat. 

We need confidence, but not to the point of arrogance. 

We need love, but not to the degree that we forget to make rational decisions.

Every good thing, is good in moderation.