In Chicago, Baltimore, all those other cities HNers turn up their nose at you might get shot in a convenience store robbery, you might get knifed by a mugger, but realistically the overwhelming majority of the violence is drug dealers and users and distributors settling scores amongst themselves (because they can't use the courts to do it for them).

Contrast with SF where the overall amount of violent crime is lower but it is much, much more concentrated toward the randomly targeted crime targeted at people not already involved in activity beyond the law end of the scale meaning that your odds of getting shot in a convenience store robbery or knifed by a mugger are higher in SF than a "normal" city of equivalent violent crime rates per capita.