FASHION : Mad Hatting : A baseball cap used to cover a too-short haircut leads to a white lie and then the truth--big mistake.

My neighbor was excited. She and her husband had just gone to a therapist because they’d been having Serious Problems. Now, she said, things were looking up.

Instantly, I knew we were coming from different worlds. As a single mom, Serious Problems around my house are things like no milk left for morning coffee. Or wet socks for the kids because I forgot to put them in the dryer. Or a phone call from the school informing me that they simply cannot lend my children any more lunch money and what did I plan to do?

They don’t train therapists for things like that.

“We just weren’t saying what was really on our minds,” my neighbor explained. “We couldn’t go on that way. Neither of us was confronting what was wrong.”

What was wrong, she said, was that neither had been telling the truth about the other. Instead of saying what bothered them, irritated them or drove them crazy, they both had kept it all bottled up inside.

The remedy for their alienation was simple: “Our therapist suggested that we try telling the truth--to everyone--for a week. We have to say what we really think so we can learn to relate in a new, exciting way.”

She paused and peered thoughtfully at me. “Is that a pimple on your nose, or what?”

Now, for most of my life, and certainly always with my kids, I have advocated telling the truth. But over the years, experience has been a great teacher. I now know there is a function for white lies, half-truths, evasions, skirting the issue and calculated omissions:

No matter how nicely the information is solicited, for example, never disclose the number of your previous marriages on a first date.

And no matter who asks, never tell why you won’t be going to the company Christmas party (“The electrician said he’d be showing up sometime between 8 a.m. and midnight” worked pretty well last year).

And no matter how many colleagues comment on your odd-ball choice of clothes or accessories, never admit to anyone that they weren’t really featured on page 76 of Vogue.

That last one I learned the hard way.

A few years ago, I went to a hair salon and ended up with a cut so short that I looked like a punished French World War II collaborator. To hide it, I donned a baseball cap and indignantly told curious colleagues that it was the latest rage. But as soon as I came clean about the ruse to one person, the gig was quickly up.

The trouble with this kind of truth-telling, of course, is that it can come back to haunt you. In just about every magazine I’ve seen lately, at least one “hot new look” has featured a baseball cap.

There was the recent picture of Princess Di wearing a cotton one with jeans. And Glenn Close wearing an embroidered one with a dress. And Madonna wearing a solid-colored one while jogging. And Janet Jackson wearing a velvet one on a TV interview.

In classic boy-who-cries-wolf fashion, I wore one to work the other day and no one believed me when I said it was in Vogue.

No one, that is, except a few people in the know. “I’ve even seen women in New York wearing them with fur coats,” said Susan Tildesley, director of the Headwear Institute of America, a New York-based trade association. “Baseball caps are headed toward record sales of more than $1.5 billion in 1991, and we’re projecting a 15% increase for next year.”

Tara Pielaet of the Village Hatter in Ventura also could vouch for me. “I think it’s popular now because it says that a woman can dress up a man’s hat and make it feminine,” she said. “They’re buying black velvet baseball hats for formal stuff and ones with rhinestones to coordinate with their outfits. I see a lot more women wearing them.”

Department stores around the county, including Bullock’s and The Broadway, have also recognized the hats’ increased popularity. You can now buy velvet caps with faux pearls, silver- and gold-toned caps, caps in a wide array of solid colors and even ones with multicolored rhinestones.

Personally, I like this trend. No one looks bad in a baseball cap, and it’s difficult to take yourself too seriously when you wear one.

Even, it seems, if the cap in question has embroidered Indian elephants and mirrors on it.

I asked my neighbor what she thought of it.

“Well, it’s sure interesting,” she said, hedging.

I didn’t know what happened to her say-what-you-really-think experiment, but her answer was fine by me.

Kindness, I suppose, is sometimes a far greater truth than honesty.