Even as a child, I had no killer instinct.

Competitive girls always seemed to be bouncing on the balls of their feet, looking for a challenge.

They were the first to spike the volleyball, the first to score, the first at bat.

I have no competitive streak. I don't even have a competitive pinstripe.

If I were a predator, I'd have died out long ago.

Some people find their competitive zeal in adulthood. Many women discovered a desire to compete when the world realized women could run marathons and still bear children. I admire these women. I admire all competitive women, in fact, though my lip still curls when I recall an extremely athletic girl in my high school class -- not because she was talented, but because even in the biology lab, she raced to be the first student to touch a cow's eyeball. (As it turned out, she needn't have hurried; she also was the last one to touch it.)

But now, later in life, I've discovered a fierce desire to win. And not just to win -- to smash, thrash, trounce, whip and eviscerate my opponent. It's exhilarating, this urge to shellac something like a decoupage kitten.

For the first time, I understand those girls in my gym classes.

You want to know what rouses my previously dormant competitive nature? I'll tell you: Products designed to be used up so we'll buy more to use up so we'll buy more. Take shampoo. I realize a bottle contains a finite amount of liquid. Eventually, a person uses the last drop and has to buy a new bottle. Fine.

It's the directions on the bottle that rile me. "Shampoo, rinse. Shampoo again, rinse," they say.

Now, maybe in pioneer days, when people bathed infrequently -- in the nine Little House books, Laura might have washed her hair once -- shampooing twice consecutively was necessary.

Those of us who shampoo daily, however, can scrape along with a single sudsing.

And if we do, the shampoo will last twice as long as the bottle thinks it will. Bam.

Now soap. Bar soap turns into a sliver overnight.

When I'm down to a translucent ellipse, the contest begins.

How long can I soap with the slick little wafer before it smooshes into a glob or shoots out of my hands and lands under the radiator?

The makeup situation is like the Middle East, only more complex.

Each kind has its own rules and its own dangers.

For example, the internet says to throw away mascara after three months. "It's a breeding ground for bacteria," it says.

"But the tube's not empty. It cost $15.99," you say.

"Do you want an eye infection?" the site replies.

Of course I don't. I also want to rub my eyes, which is why I gave up mascara years ago. But if I used it, I'd spread it with a butter knife so the tube and three months come out even. Of course, the real question is, if mascara has a three-month shelf life, why do the tubes hold enough for half a year?

Well, never mind. My favorite event is the disposable-razor competition.

Exactly when are you supposed to throw away a disposable razor? After one use? After one leg?

When a men's disposable-razor maker suggested four days per blade is reasonable, I selected a yellow razor from the packet, bouncing on the balls of my feet.

Days passed, then a week. Then two weeks, a month. The furnace started coming on in the morning. I read several books. Seasons changed; empires rose and fell. It began to seem I would never use up this razor.

Then we left town for a week.

I took the razor, of course, along with a spare.

That broke my streak. I started using both razors, yellow and pink. I may go on like this until the end, and it will be noted during my eulogy: "She used the same two disposable razors for the last 22 years of her life."

Too bad no cow eyeballs are around. I feel like poking one.

Write to Margo Bartlett at margo.bartlett@gmail.com.