"If there aren't any sparks, forget it," my friend was saying. We were discussing that strong initial attraction between a man and a woman known as "chemistry." She said she won't even go on a second date with a man who doesn't turn her on at the outset.

Her candor stunned me at first. I thought she was being harsh and quick to judge. After some thought, however, I had to admit I feel much the same way. I've never been blinded by "chemistry," and I'm not a "hopeless" romantic who believes in love at first sight. (Just what is it we love when we love at first sight? Certainly not the whole person.) But I'd be lying if I said the initial rush didn't matter.Perhaps sparks can ignite over time. Indeed, if chemistry has proven an unreliable barometer of lasting love for us in the past, maybe we should give the excitement a chance to build with someone we already know to be a good person.

"We human beings put a great deal of emphasis on physical appearance," says Tucson, Ariz., psychologist Kevin Leman, author of the book "Were You Born for Each Other?"

"Most of us seem to think we can see into a person's character by the way he looks," Leman says. For instance, "Men make the mistake of thinking that a woman with a great pair of legs also has a terrific personality - but it ain't necessarily so. I tell men to be careful not to confuse their libidos with their hearts," he says.

Our requirements vary in the looks department. Some people have ridiculously specific desires (i.e., so-and-so must have strawberry-blond hair, hazel eyes, and stand taller than 5 feet 8 3/4 inches). Others insist they don't care about looks at all. Most of us probably fall somewhere between the two extremes.

Intellectually, we know we can't base a long-term relationship solely on the physical. But we trip ourselves up emotionally by falling for someone who looks good outside but is numb - or even cruel - inside. We let the chemistry overwhelm us to a point where we can't see straight . . . into a person's heart and psyche. How many times must we get burned before we learn?

To make matters worse, we try to change him or her once we learn the interior isn't so beautiful. If we feel the need to change someone, that person was probably wrong for us in the first place. We can't fix someone's inner problems - and for our own sanity, neither can we ignore them. Pursuing an attractive but emotionally screwed-up person can only lead to heartache.

Another book shrink said something worth remembering. She said love should make you feel full, not empty. If you feel vaguely empty or emotionally unsatisfied after being with this wonderful lover, beware. It is likely you will ALWAYS feel empty with this person - no matter how potent the chemistry.

"My phone rings off the hook," writes David, 32. "Not with invitations or dates, but to provide a shoulder for some woman friend dealing with the jerk she's seeing. It never ceases to amaze me, the crap women put up with from men," he says.

"I adore these women. I'd give anything to let just one of them become more than just a `special friend.' I know there has to be chemistry. Sparks flying and all that. I look for that myself. But I've been around the block enough to know that nature does nasty things to our bodies in time," he concludes.

Maybe it's time we see "sparks" for what they are - pleasant and exciting, but more an indicator of lust than love. By honestly recognizing the difference, maybe we can avoid some pain. A protective sheath of healthy skepticism helps, too.