Extremes are usually unworthy paths to follow.  If a person sees himself thinking or acting in an extreme manner, he should reign himself back to the middle of the road – which is generally the good and upright path.  This is why God, in the Biblical chapter of Exodus, instructs Moses to find people who are not extremists to fairly judge his people. 

Some examples: 
You should not feel anger most of the time, nor should you mostly feel apathetic.  Anger is appropriate only when you can succeed in not repeating a hateful situation.  Apathy, on the other hand, solves nothing.  You leave results to others.
You should not be a glutton.  Better to simply eat – and enjoy – what you need to sustain your body.  Modest eating habits can frequently be found in the righteous.
You should not be overly miserly nor should you squander all your money.  Better to give to charity whenever you can, and lend appropriately to those in need.

If your demeanor generally gravitates toward the center, midway between extremes, you are wise.  Your human nature can push you toward extremes.  Don’t let it impact your spiritual center.