I predict that as we see an increase in the number of mobile phone headsets (you know, those Bluetooth things hanging from yuppies' ears) our society will also see a correlative rise in the number of attacks by crazy people.
It used to be that if someone was talking to themselves you had an immediate warning to keep your distance. The person was obviously crazy, and crazy people can do crazy things. For example, biting. The judicious course of action is to avoid the crazies, which helps keep them from doing said crazy things (you know, biting).
With the increase in Bluetooth usage, more and more people appear to be talking to themselves when they are in fact just on the phone. I've heard plenty of people complain that they mistake headsetters for crazies. And to be sure, this is annoying. You end up going out of your way to avoid a crazy when you really didn't have to; it was just a yuppie, camouflaged as a crazy.
As annoying as that can be, I think most people have overlooked the danger of the opposite result: mistaking crazies for headsetters. Contemplate for a moment a world in which Bluetooth is so pervasive that when you see someone talking to themselves your first inclination is to assume they're a headsetter. No more does it occur to us that the person may be a crazy. Just as now we avoid headsetters for fear that they're crazy, we will someday fail to avoid crazies as a result of our complacency with headsetters. The initial response to a person talking to himself won't be one of self-preservation (Stay away! Don't bite me!), instead it'll be one of apathy (Oh huh. Another yuppie.).
Without the impulse to avoid people talking to themselves, more and more people will inadvertently put themselves in harms way, by getting too close to an actual crazy person. And then my friends... that is when the biting will start.
Another interesting thought on Bluetooth (hat tip to my dad): Will our constant use of mobile headsets create an evolutionary advantage for people who are better able to utilize the device (that is, people with one large ear.)? After all, they'll be better able to communicate, therefore more likely to procreate, and therefore more likely to breed a race of humans with one gigantic ear. Creepy. Also, they'll probably have tiny fingers. Freaks.
Crazy for feeling so blue