We seem to never be contented, always wanting what we can't have. Nowhere does this prove truer than with hairstyles. Women with stick-straight hair want waves, and those born with twisty curls covet the sleek straight look. And forget about frizz: No one requests those frazzled dry fly-aways at the salon.

In recent years, shiny, blown-out straight hair has been the most sought-after style. And women will go to great lengths and expense to get their hair to behave according to current fashion. The straight hair arsenal includes flat-irons, blow-dryers, and all kinds of products claiming to fight fly-aways and un-kink curls. Many women even pony up hundreds of dollars to stylists to get a few months of straight, frizz-free hair through processes like the Brazilian blow-out or the Japanese hair straightening treatment. Do these products and processes make any difference - or do they damage your hair? Let's smooth over some of the most common questions about hair-straightening:

First of all, why is my hair curly or wavy and not straight? The shape and thickness of your hair depends on the shape of the hair follicles out of which it grows. And the shape of your hair follicles depends on your genes.

And why does straightened hair look so shiny? The answer to this is all geometry and optics. Hair with curls or waves has lots of curves and angles off which light bounces, but straight hair reflects light and appears shiny.

Does blow-drying harm my hair? Your hair is dead tissue, so you can't really make it any deader. But blow-drying can weaken your hair's cuticle, which protects it from damage. All of that heat can also sap hair of moisture that it gets from its still-living hair shaft - moisture that protects hair from breakage and other damage.

That said, blow-drying is a cheap, easy way to straighten your hair on your own. If you plan to blow-dry your hair on a regular basis, be sure to condition your hair regularly, too. You might also consider adding a diffuser to your blow-dryer, or experimenting with products that protect your hair from heat damage.

Will flat-ironing damage my hair? Like blow-drying, a flat iron applies heat to your hair, and heat can cause damage. Reduce damage by using a heat-protective product or applying leave-in conditioner before you take iron to hair.

Is relaxing my hair safe? Relaxers are not really very relaxing. Harsh, corrosive chemicals applied to the hair cause a chemical reaction that breaks down the protein in the hair, making the hair more pliant to straightening. A neutralizer is then used to set the new straight style. While relaxers may be quite effective at getting hair straight, they weaken hair, making it more prone to breakage. Not to mention that those caustic ingredients can irritate your skin. And since your hair will grow back the way it was before, you may decide to relax it again. Wait at least 6 weeks to protect your hair.

Is the Brazilian blow-out process safe? Women who've longed for straight, shiny locks have cried in joy when they look in the mirror after a so-called Brazilian blow-out (BBO). This South American hair phenomenon has become hugely popular - despite the hours you'll spend in the salon seat and the steep fee that can run you upwards of $600. A keratin formula (your hair is mostly made of a protein called keratin) is applied to the hair, which is then flat-ironed at very high heat to a smooth lustre. After a few days without washing, hair should be set in a straight style for a few, frizz-free months.

Does it sound too good to be true? Well, some formulations - those considered most effective - contain formaldehyde, a known human carcinogen. And once pressed by the flat iron, the formaldehyde heats up and becomes an airborne risk. One woman in Brazil is reported to have died from the fumes created when she did the treatment on her own hair. And Health Canada issued a warning in 2010 for Canadians to avoid a product called "Brazilian Blowout Solution" (manufactured by Brazilian Blowout of California) because it has been found to contain unacceptable levels of formaldehyde. If you are interested in having the process done, ask salons if they use formaldehyde-free products - or at least products containing 0.2% formaldehyde or less, the limit advised by the Cosmetic Ingredient Review Expert Panel (CIR).

Is Japanese hair straightening treatment safe? Like the Brazilian blow-out, this straightening method will also cost you a pretty penny - somewhere in the $500 or higher range. The Japanese method is thought to work in a way similar to chemical relaxers, breaking the protein bonds in hair and making it easier to straighten. And like relaxers, the treatments can damage. Effects last about 6 months.

The frizz factor
If your hair is relatively straight, humidity in the air will probably cause your hair to frizz. This happens because moisture from the air gets into your hair and causes the proteins inside to plump up. Some protein will plump up more than others, which is what causes that messy, irregular frizz.

Those with curly hair are more prone to day-to-day frizz. Also, over-brushing can stretch and stress the proteins on the surface of your hair, causing the hair to break and split and, thus, to stand on end or frizz out.

With straight hair so high on so many women's wish list, hair care companies offer up all sorts of frizz-proof products, from shampoo and conditioner to serums to finishing sprays that add polish and sheen. Some of these products work by conditioning the hair, which weighs it down, smoothes the surface, and helps it lie flatter.

Other products use silicones and resins, which create a protective layer over the surface of the hair so it will not be affected by humidity. Newer formulations contain polyfluoroester (PFE), which is like Teflon for hair, reducing surface tension and keeping moisture from soaking into the hair.

Amy Toffelmire