In a perfect world, one would never feel such intense anger at another person that one would actually wish them harm. Alas, we do not live in a perfect world.
When emotions run high, some people are able to maintain their calm, while others may take action against the perceived enemy. Somewhere in the middle of these two responses is the reaction of uttering a curse on the other party. While “uttering a curse” sounds very much like magic and voodoo, a curse is simply the opposite of a blessing. Whereas a blessing is a prayer that good things befall others, a curse is a prayer that harm to befall them.
Curses, known in Hebrew as klalot, are mentioned several times in the Torah. God even warns the Jewish people of the curses that shall befall them if they turn from the Torah.
On a personal level, the Torah twice prohibits cursing: (1) “You shall not curse judges, and a prince of your nation you shall not curse” (Exodus 22:27) and (2) “You shall not curse a deaf person” (Leviticus 19:14).
Why specifically judges and princes? Perhaps because when a person loses a judgment in a court of law, the only outlet for the personal disappointment and anger is to blame the judge or, in certain cases, the local ruler.
Why specifically a deaf person? Cursing a deaf person appears to be a safe, seemingly harmless, way of blowing off steam. However, words have power, whether they are heard or not. In truth, most people curse others under their breath or well out of hearing range. Thus, we are taught that proximity, or the ability for the curse to be heard, really has nothing to do with the negative energy released by the prayer that has already been uttered.