He repented his thoughtlessness.

他后悔自己的轻率。

Because rude behavior in children is more often the thoughtlessness than of deliberate aggression, criticism， namecalling and orders only make a child angry and defensive.

孩子的礼貌行是缺乏考虑的结果，而是故意冒犯别人，批评辱骂和命令只会使他们恼怒，产生抵触情绪。