There is a reason why God included gentleness and self control as fruits of the spirit. These traits do not come naturally to most of us and impatience and intolerance are sometimes easier traits to find. We often think that if someone has done wrong that there is a need for punishment. That if someone has spoken harshly then let us respond in like manner.
Solomon teaches that a soft answer turns away wrath: but grievous words stir up anger. (Proverbs 15:1) There is a reason why Jesus cautions us to turn the other cheek and to not repay evil with evil.
There are some situations where a soft spoken word and a bit of gentleness can do far more than a harsh word of criticism. Mistakes are often a sign of struggle and it is human to err. If being harsh and punitive has not worked so far then try speaking gently to see if this garners better results.
For ye have need of patience, that, after ye have done the will of God, ye might receive the promise. (Hebrews 10:36)