Maybe this is in reference to "ignorance is bliss?" Consider how righteous men in times past have been vexed in their spirit at their surroundings (Lot, for example). Or, even in wisdom you see acts of foolishness and are perplexed, bothered, or even make judgments (improperly, high and mighty). To "bring in abundance" (over much) righteousness or wisdom, could be a double edged sword. In one respect they are both good to have, and yet in another one ought to be careful ("judge not lest thou be judged").
Judge men and you might make yourself a hypocrite, pride comes before the fall, right? In the next verse (17) it says to not be "over much wicked", and I'm sure that isn't an encouragement to be wicked at all, only pointing to its consequences being an early death. Likewise, what are the, possible, consequences of being "overly" righteous or wise, or even excelling in the two?