I know people who, if you hog the sidewalk, cut in front of them at the supermarket or let the elevator door close in their face, will shrug it off. No problem.

But smile at them and say "Have a nice day!" and they get angry.

I don't mean the totally impersonal "have a nice day" at the end of some pre-taped telephone message or the sarcastic "have a nice day" from the cop who has just given you a ticket for jaywalking. I'm talking about the pleasant "h.a.n.d.," delivered with a smile, after you have made a purchase, or engaged in elevator chitchat, or taken a taxi ride. Why does such friendliness drive so many people up the wall?

It doesn't help to ask them. They'll tell you the phrase is "empty of meaning," and then they'll say something profound, like "see ya" or "so long." They'll tell you it sounds too much like an order, or suggests that you are too stupid to have as nice a day as you can without their inane suggestion, and then they'll order you to have a "good night."

One man told me "It's too 'California.'" Too much like smile buttons or "good vibes" or people talking about their "space." For sure. But can no good thing come out of a state that can deliver decent table wine, breath-taking pallisades and Carmel? Does "have a nice day" really belong in the same category of aggressive behavior as telling a stranger on the street "Jesus loves you"?

I'm mystified by the depth of feeling against what strikes me as, at worst, an innocuous remark. I've read about: an elderly woman who responds to "h.a.n.d." with "Why should I have a nice day? I'm old and tired"; a Virginia man whose disconcerting response is "I'm sorry, but I've made other arrangements"; a Marylander who has founded ATAHAND -- the Association to Abolish Have a Nice Day--whose only membership requirement is that you instantly tell anyone wishing you a nice day to drop dead.

Some of the less aggressively nice among us would rather go back to the old forms than use the modern- but-offensive one. The problem is that no one can tell you what we used to say to each other. "Peace"? "Good day"? "See ya around campus"? "Twenty-three skidoo"? Did any of these expressions seem more sincere, more fraught with meaning, less namby-pamby?

It's probably pointless to try for meaning in a routine expression. It starts out meaning something sincere and ends up pleasantly meaningless. And so what? Do you really want a virtual stranger or a not-so-close colleague showing sincere interest in your spouse and kids?

The problem, I'm afraid, is not with the expression but with the growing number of soreheads who will always find something to gripe about.

I think I'll go right on with "have a nice day." And if they don't like it, the hell with 'em.