Kindness means that one must avoid using harsh words or harsh attitude in anger, and behave and speak with Kindness. If someone has to be checked or if a difference in opinion is to expressed, one should not be rough or harsh, but speak softly and kindly. if a younger person has to be trained and strictness can not be avoided, it too should be adopted in moderation or to the extent needed.
Kind behaviour also implies that one must not argue or quarrel with others on every issue and think well of them as far as possible. Even haggling over price should not be harsh or acrimonious. One should be ready to accept another’s viewpoint if it is acceptable, and when if it is not so one should withdraw from argument. It is not good to compel others to agree with one,s own viewpoint and to force them into submission.
May ALLAH make us enable to act upon his Deen (ameen)