1. When you show up late, you're not just throwing off their schedule, you're compromising your cut. The refinement of your cut happens in the last 10 minutes -- after your hair is dry -- and it's crucial. If time is tight, your stylist will have to rush through it.

2. Not only is your cell phone conversation annoying, it's messing up your hair. When you're on the phone, you tilt and move your head. Some stylists say that even gum-chewing causes slight movements that can lead to an uneven cut.

3. A running critique won't improve the result. "Don't micromanage a cut in progress," says stylist Shin An. "Make sure you have a detailed consultation -- with photos for reference -- then let your stylist concentrate." If you feel your cut is veering way off track, ask your stylist to stop so you can discuss your specific concern ("My bangs are getting too short").

4. Myth: A good stylist can talk and skillfully cut hair at the same time.
"Cutting hair is a technical craft that requires a lot of concentration," says salon owner Eva Scrivo. "Can you carry on a conversation while you're typing? No. I see a lot of haircuts with typos." Catch up with your stylist before she starts cutting, then pick up a magazine and let her do her work.

5. Myth: All highlights are created equal.
Most colorists use foils to create highlights, but balayage* can give more sun-kissed and natural-looking results, says Marie Leppard, senior colorist at the Julien Farel Salon in New York City.

6. Myth: Stress created gray hair
No amount of fretting can affect the production of melanin and the enzymes that influence pigmentation in your hair.

*A process of highlighting hair by painting on bleach without using foils (from the French "to sweep").

Related on HuffPost:

Hair Mistakes That Make You Look 10 Years Older
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  • Mistake #1: You Have An All-One-Length Cut

    Without layers, your hair won't have that magical, youthful quality that stylists call "movement." Long layers remove weight from the bottom half of your hair so your style can swing and bounce. And while blunt edges accentuate lines in your face, layers have a softening effect. Consider side-swept bangs if you want to make your face look a bit rounder and your cheekbones stronger, says <a href="http://evascrivo.com/salon/">New York City hairstylist Eva Scrivo</a>, author of <i><a href="http://www.amazon.com/Eva-Scrivo-Beauty-Techniques-Knowledge/dp/1439164711">Eva Scrivo on Beauty: The Tools, Techniques, and Insider Knowledge Every Woman Needs to Be Her Most Beautiful, Confident Self</a>.</i>

  • Mistake #2: You Have Shelves Full Of Styling Products

    If you're using more than one styling product in an effort to make your hair look fuller, your plan may be backfiring. "Mousse and gel and hairspray can give the hair lift for a few hours, but they also make it look stiff and sap its shine -- a very aging combination," says Scrivo. If you have a well-layered haircut that's not too heavy at the bottom, you won't need to load up on styling products to achieve volume. One dollop of lightweight mousse will do the trick; once hair is dry, use a drop of silicone serum to add shine.

  • Mistake #3: You're Very Blond

    Your skin loses color with age, and over-bleached hair compounds that natural washout by draining the warmest tones from your complexion. Instead of going all-over blond, try a darker base color with golden strands woven throughout, says <a href="http://www.lisachiccine.com/">New York City hairstylist Lisa Chiccine</a>. When you talk to your stylist about highlights, ask for warm colors like butter and honey; avoid cool, ashy tones like platinum and beige, which can make skin look tired and sallow.

  • Mistake #4: You Have Dry, Frayed Ends

    As you get older, your hair loses not only pigment but also its ability to retain moisture. Keeping it smooth and glossy -- hallmarks of youth -- requires a little more effort. Do a deep conditioning treatment at least once a week, don't shampoo more than every other day, and get frequent trims to avoid split ends.

  • Mistake #5: You Have A Deep, Dark Hair Color

    Solid black or brown hair can highlight shadows on the face, drawing attention to lines and bags. If you're fair-skinned, a dark hair color also accentuates the contrast between your hair and scalp, which makes thinning more noticeable. A few highlights around the face and at the crown of the head add softness and make a dark hair color appear more natural. "You don't want to look like you're wearing a wig," says Chiccine. Her rule of thumb: Don't dye your hair as dark as it was in your teens and 20s; a shade or two lighter will be more flattering in your 30s and beyond.

  • Mistake #6: Your Hair Is Super-Straight

    A lank hairstyle makes your face look long and drawn. (Plus, if you have naturally wavy or curly hair, the hot tools required to achieve straightness leave your hair dry and dull.) If you have naturally fine, straight hair, ask your stylist for long layers and comb a lightweight mousse through damp hair from roots to ends before airdrying or blowdrying (avoid heavy styling creams or serums). If you blowdry, use a round brush to create soft curls at the ends of the hair; setting dry hair with Velcro rollers will also create softness and add volume to offset any drooping in the lower face.