EDIT: just out of curiousity let me pose this question for those who see CCW as some sort of safety assurance or deterrent.....
in most places Ive ever lived..... and where I live now...... you can still hip holster a handgun as long as its clearly visible (with the normal exceptions like in bars, schools, etc etc)
so for those who live in such areas why do you see a need to CCW instead of just hip holster??
In a word: deterrent.
Knowing that law-abiding, TRAINED citizens can, and DO, carry concealed weapons, a person who is out to do harm (robbery, rape, assault, etc) will be more reluctant to do so. There will always be that thought in the back of the mind, "If I try to rob this guy, will he be able to shoot me? If I try to grab that woman over there, will she be able to bring lethal force to her aid?" The effect on the number of violent crimes when disallowing then allowing law-abiding citizens to carry concealed lethal weapons has borne this out.
If someone who is out to do harm is in an environment where only open carry is allowed, that person can shop around for an unarmed individual to attack. This also would be an incentive to the person who is up to no good to conceal his weapon: he would look like a law-abiding, UNARMED person rather than an armed potential assailant.
Now abouth those "rage" incidents.
In an all open-carry environment, people are more prone to control their anger when they can plainly see the person they are about to go off on is armed.
If someone who is openly carrying a weapon is acting all agitated, people in the surrounding area will be vigilant to that person's every move and TRAINED individuals will be ready to react APPROPRIATELY.
Second, an individual who applies for a concealed weapon permit must undergo a background check which includes a records check and interviews of acquaintences. If the acquaintences recommended by the applicant are not that sterling in the eyes of law enforcement, other people are asked about the applicant's character. Before even applying for the permit, a person must receive (and PASS) the appropriate training in the legal aspects of the use of lethal force as well as local weapons laws, as well as proper handling of firearms.
As a rule, concealed weapons permits are not issued to people who are prone to lash out in anger.