Memetic Hair

"Attention duelist! My hair is an internet phenomenon.

Kemo Yu-Gi-Oh! The Abridged Series"

Almost anything can become a meme, whether it be an outfit, a badass, or a picture of an animal doing something funny. Hairstyles are by no means immune to Memetic Mutation. Hair is a device creators often use to convey information about a character to the audience. For example, a girl with pigtails or a girl with a Mohawk are likely to be very different. In non-visual mediums, largely due to The Law of Conservation of Detail, it's seldom an arbitrary choice on the author's part to describe hair at all.

Sometimes somebody's hair is so stylish or unique that it becomes associated with that person or character. In fiction, weird hair can become so recognizable that to change it would be like losing part of his or her personality. In Real Life, a celebrity's trademark hair could even become a trend, even if was around long before they made it popular.

See Hair Tropes. Note that Anime Hair is especially likely to be subjected to this. Einstein Hair is a subtrope.

Anime and Manga

 * Yu-Gi-Oh has one of the most extreme cases of Anime Hair the world has ever seen
 * Kemo, as noted in the page quote.
 * Astro Boy
 * Dragon Ball's Super Saiyan hair
 * Sailor Moon, the Trope Namer for Odango Hair.

Comic Books

 * Tintin's "duckbill" bangs. Lampshaded several times in the recent film adaption- no matter how many times he tries to flatten them down, they bounce right back.

Film

 * Princess Leia in Star Wars
 * Seneca Crane's beard in The Hunger Games.

Literature

 * Discworld: Archchancellor Ridcully's uniquely-groomed beard with mustache.

Live Action TV

 * Rachel's hairdo in the early seasons of Friends.

Video Games

 * Cloud's ridiculously spikey hairdo in Final Fantasy VII
 * Kaoru Tanamachi slightly mussed hairstyle in Amagami has earned her the Fan Nickname of "Sex Hair."
 * Ramza Beoulve from Final Fantasy Tactics is known for his ponytail and Idiot Hair.

Western Animation

 * The Simpsons:Marge Simpson's trademark hive

Real Life

 * Farrah Fawcett got the style she made popular named after her
 * Figure skater Dorothy Hamill
 * Albert Einstein: there's even a whole other trope devoted to this
 * Betty Page's hair
 * Justin Bieber
 * Mr. T's mohawk hairstyle, which he claims he copied from a African Malinka warrior he saw in a National Geographic.
 * Veronica Lake's over-the-eye look was named after her
 * Weird Al's long curly hair and pencil moustache. For a while after he shaved & got a haircut, he wore wigs & a fake 'stache for public appearances just so he'd look like himself, but eventually abandoned them.
 * Adolf Hitler's mustache (or Charlie Chaplin's)
 * Chuck Norris's beard.