Aside from the reasons Botnst listed, how about the effect open carry has on people around you? I don't know anyone who would not be creeped out by a guy wearing a gun like that in an open fashion. A few years ago we had some people celebrating Virginia's lenient gun laws by making a big show out of wearing guns in bars.
Virginia gun-rights enthusiasts celebrate Va. law on firearms in bars Bunch of self-important jackasses.