A long time ago,

A long time ago, I discovered I was allergic to cola drinks. Now I discover I'm sensitive to urban wariness, too.

Back then, I tried an elimination diet to confirm my allergies. I stopped eating all the foods I was allergic to, then one by one reintroduced them to my diet. This helped me to find out not only whether I was allergic but also what symptoms were associated with each food.

Coke gives me a headache. I was astonished to find that out. After all, I'd been drinking it almost every day for years and never noticed the nagging back-of-the-head pain. I was just contantly cranky and irritable.

Being alert on the streets of Chicago also gives me a headache. I get the same cranky irritibility when I have to spend my time on the street being alert for possible dangers.

"Who's that across the street? Is there enough distance between me and that car that's been circling the block? Is that group of men on the corner a threat to me? How can I avoid them? Is there an escape route? What if...?"

This internal dialogue flashes through my mind quickly, expertly and without conscious effort. I can converse with my companions, even laugh, but I'm on edge.

Edginess is not a feeling I enjoy. And here in Japan, even in Tokyo where the train companies are planning women-only carriages to avoid unwanted groping during the drunken holiday season, I never feel the pain of urban wariness.

I don't drink Coke anymore. Should I avoid US cities, too?