It's the moment of truth. I've just had my hair cut. I've been shown the back of my head in a mirror, and my hairstylist has whipped the smock off me.

I rise from the chair and am suddenly frozen with indecision. Call it Tip Anxiety. Do I pull out my wallet and give her a gratuity? I gave one to the woman who shampooed me earlier, but should I have done that? And how much should I tip, anyway? Some percentage of my bill? A flat five bucks? More?

Do I put the money in her hand? Or place it on the counter of her work station? And what if I don't have exact change? Can I add a tip to my credit card receipt? Or stick a note in an envelope that says she'll find a tip later in the day under a rock at the northwest corner of 16th and K?

Deciding whether to attempt a kiss on a first date is easy next to deciding how to tip a service provider.

I hate worrying about the whole thing, and I'm not the only one. There have been some interesting changes in the world of tipping lately, including something downright heretical: not tipping at all.

First of all, is tipping a reward for good service or protection against bad service? Is paying a tip a way to buy something you should be getting for free (good service) or is it a way to guarantee that something bad won't happen to you? If it's the latter, we're getting uncomfortably close to extortion.

And what about the complex rules? A Web site devoted to tipping -- www.tipping.org -- lets tippers and tippees kvetch. It also provides some tipping guidelines: skycaps, $1 per bag; hairdressers, 15 percent of bill (unless it's the owner); dog groomers, no less than $2 per dog; bellhops, $10 for bringing your luggage to your room; hotel chambermaids, $5 a night.

But I carry my bags myself, and shouldn't I expect a clean hotel room as a matter of course? Part of me thinks that tipping should be determined by my behavior, not the service provider's. For example, if I trash my hotel room in a drunken rage, I should tip the maid. If I've grown my hair long and rolled it around in creosote and lawn clippings, I should tip the shampoo girl.

I do enjoy giving some tips. I consider beer a sacrament, so I always tip the bartender. The five guys who moved us into our stair-filled house last year worked hard. I bought them lunch and gave them each 20 bucks. I felt like Rockefeller.

While waiters and waitresses love to share tipping horror stories, I think most Americans know that the law allows servers to be paid less than the minimum wage and thus they must be tipped. But does your tip reward your waiter? Sort of. At many restaurants, the evening's tips are pooled then distributed in something called the "tipout." The bulk goes to your server, but percentages are sliced off for busboys, "food runners," bartenders and greeters.

Then there's the controversy brewing (heh-heh) in Internet chat rooms such as www.starbucksgossip.com over whether to tip baristas. On one side of the argument is "Becca," who wrote: "Tipping makes us love you, and when we love you we make better drinks for you, give them to you faster, etc." On the other is "Hirayuki": "If you are deliberately making it incorrectly or delaying handing it over, you should be disciplined or fired."

Tipping: buying love or bowing to extortion?

Three years ago, Domenic Cicala, owner of Gaithersburg's O'Hair Salon + Spa, noticed that tipping had become overly complicated. Some clients were tipping five or six people as they paid their bills: the shampoo girl, the stylist, the colorist, the nail technician, the aesthetician.

"It was crazy," said Domenic. He himself was too busy to deal with the cash people thrust at him. It piled up at his work station. "It's physically ugly," he said. "It reminds me of a strip club, with money sticking out of every place it can stick out of."

And, like many business owners, he was worried that improperly reported tips would bring the IRS down on him.

So he instituted a strict non-tipping policy. Prices were raised 25 percent, and customers were told they needn't tip, couldn't tip. "We're professionals," he said. "We charge according to the value of our services."

There may have been grumbles among his staff, but no one left.

Domenic said people who've worked in tip-intensive jobs are usually the best tippers, but he was flummoxed on a trip to Las Vegas. A restaurant bill had two lines for tips on it, one that said "Captain's tip" and one that just said "tip."

"I was stumped," said Domenic. "I wasn't going to give them 20 percent each, that's for sure."

Like haggling over the price of an Oriental rug, there seems something old-fashioned and Old World about tipping.

"Our industry has gone from roller sets to blow dries," Domenic said of the hair salon business. "There have been all sorts of paradigm shifts. But nothing is more ingrained than tipping. It will be absolutely the last frontier -- and probably the scariest one, too."

Sorry, Sally!

There's nothing wrong with being called a receptionist, unless you aren't one. In Wednesday's column, I said Sally Schwob was a receptionist at Keller Associates in Silver Spring. She's really a licensed property manager.

Carp about tips or anything else that's on your mind during my online chat, today at 1 p.m. at www.washingtonpost.com/liveonline.