Two or three in a row can relieve even more tense feelings. It allows you to vent without doing physical damage to anything or anyone. However, I don't think anyone should go around swearing for no reason. Words have power, but they lose that power through over-use. It is far better to give someone a good shock than to desensitize them entirely.
All words are useful tools.
It actually requires intelligence to swear effectively. When Americans realize that words only have as much power as you give them, then true communication can take place. Until that time, we will continue to tiptoe around each other, scared of provoking a fight. And if we suppress our emotions, we are not giving ourselves a more peaceful life, we are giving ourselves a more repressed life.