Pity, if just for a moment, the smokers. Then feel sorry for the rest of us.

Starting Monday, smoking will be banned in most Boston bars, nightclubs and restaurants. And just as fat squeezed by a girdle doesn't disappear into fat heaven but rather migrates someplace else - to your back, or that place where your hips meet your thighs - so too will the smokers be displaced to other venues.

In New York City, where a similar ban has been in effect since the end of March, they've taken to the sidewalks, inflicting their secondhand smoke and secondhand chat on innocent passersby, and the same thing's sure to happen here.

While there's been much concern about the economic impact of a ban, woefully little attention has been paid to the aesthetics of the situation.

The crackdown is going to totally change the streetscape.

Yes, we've become used to seeing smokers outside, huddled in the doorways of office buildings and theaters, frantically feeding their habits, but most don't spend hours there. They get their hit and return to their desks.

But now the smokers are going to settle in on the street for the evening. Actually, they won't be outside the whole time; sometimes they'll be indoors, eating their Caesar with grilled chicken or drinking their Shiraz.

In which case, they'll use tricks learned from parking in this town and save their spots on the sidewalk with traffic cones or chairs (folding, of course, not nice bar stools). At a really popular bar or restaurant, the empty slots could run three or four deep.

Has anyone conducted any kind of foot-traffic flow survey? Between the tourists walking three abreast, the double jogging strollers, the in-line skaters and the oblivious cell-phone talkers, it's going to get pretty hard to walk around here.

Throw Segways into the mix, and I fear an uptick in nontobacco-related smoking fatalities, as drivers going 12 mph on motorized scooters try to maneuver between the martini drinkers and the diners swallowing the last of their sweet-potato chips while fumbling for a lighter.

And you know what's going to happen, don't you? Under the theory that anything that happens in Boston worsens vehicular traffic, the clogged sidewalks will become so much of a problem that a group of do-gooders will form to advocate for widening the sidewalks, which in turn will narrow the streets, thereby making driving even more annoying than it is and parking downright impossible.

The whole North End will have to become a car-free zone.

Meanwhile, griping about the weather - a boring conversational favorite in New England - now will extend through entire evenings. Every time someone considers going out for a smoke, or returns from one, some mention will have to be made of the heat, the cold, the rain, the drought.

``Big deal,'' you may be thinking, ``I'm not going to be in any of those conversations because I don't go to bars.'' But yes, my friend, you will be. You know how drinking lowers conversational inhibitions? Anyone walking by will be fair game for a little alcohol-fueled chat.

Between that and the billowing smoke on the sidewalks, this ban might not be such a great idea after all. Yes, yes, I know it will make workplaces healthier for bartenders and waiters, but what about the rest of us? The pathetic people who never even go to restaurants or bars? Why should the fun that others are having be thrust in our faces day and night?

I don't want the smokers invading my world. Send them back in, among the party people, where they belong.