Why did they spell "why?"
Because there weren't enough pins for "oblivion"
Teenagers who are whiny, self-important, and generally trying to work their way to self-identification. The character type based off the Emo persona.
The things that differentiate and identify Emo Teens are that they dress in black, listen to strange music (specifically, the "emo" genre, whence the term comes) and generally think that they are erudite (or, at least, surprisingly coherent). The slightly better-kept ones are usually political. If the character is female, she will tend to be extremely self-conscious about her appearance, but implausibly attractive all the same.
Since Emo Teens cultivate an out-of-the-mainstream image, sometimes writers get lazy and use them as a stand-in for any variety of geekishness that isn't considered "too nerdy".
Most shows with an Emo Teen do it semi-sympathetically, where the character is at worst whiny and judgmental, but fundamentally good. However, if any character is going to suffer from an overload of Wangst, it's them.
In Real Life, most definitions of "emo" require that you act like your life sucks when it doesn't to qualify. In fiction, however, There Are No Therapists, and no matter how dark a Back Story a character has, acting even remotely unhappy is sufficient to be labelled "emo". Internet fanboards don't care if you spent the first decade of your life in a cupboard under the stairs only to discover your magical new world comes with a mortal enemy, your dad scarred your face with fire and kicked you out for valuing human life above military victory, or you came home from school one day to find that your big brother killed your parents. Suck it up, emo boy.
- Mary Jane goes through an Emo stage in the miniseries Spider-Man Loves Mary Jane. She's shaken out of it by seeing Peter Parker dealing with heavy emotional pain (his uncle dying) in a relatively dignified fashion.
- "Emo Kid" by Adam and Andrew parodies the emo subculture, as well as outside reactions to it.
I'm dark and sensitive with low self esteem
The way I dress makes everyday feel like Halloween
- MC Lars' song "Signing Emo" mocks the kind of music Emo teens likes by telling the story of the fictitious band Hearts That Hate and their One-Hit Wonder "Cry Tonight".
- The title of a Foo Fighters song takes a jab at Emos: "Cheer Up, Boys (Your Make Up Is Running)". In an interview Dave Grohl mentioned how the Reagan administration engendered hardcore punk (which he was a part of) and the Bush admin. engendered Emo. Back then, kids were shouting about it, now they're crying about it.
- Parodied by the Pet Shop Boys song "Miserablism".
Just for the sake of it, make sure you're always frowning (Angst! Angst! Angst!) It shows the world that you've got substance and depth
- Also parodied by Electronic's "Getting Away With It", as a Take That! against The Smiths singer Morrissey and his fandom. The two bands shared a guitarist.
I've been walking in the rain just to get wet on purpose I've been forcing myself not to forget just to feel worse
- Lampshaded in The World Ends with You when Neku plays Tin Pin to suppress his "Emo Urges" during Another Day.
- Survival of the Fittest version 1 had tons of these characters, even Hawley Faust had elements of the trope (including suicide attempts). Versions two and three dropped off this trope, but didn't abandon it entirely; Damien Carter-Madison and Eduardo Trinidad-Villa both stood out as this type of character.
- 8-Bit Theater has Vilbert Von Vampire, who is an Emo Teen Vampire fond of poetry and LARPing.
- Haley from The Order of the Stick went through an Emo Teen period in her life. In fact, it was the memory of her Emo Teen self that tried the hardest, out of all of Haley's seen personality traits, to hook Haley up with Elan.
- "Hope is Emo", a video series by the same people that did Ask a Ninja, featured Hope, an incredibly stereotypical Emo girl, answering questions from viewers, and at least once each episode breaking out into tears about some minor thing (the first episode had her crying over words being killed when you erase them from the blackboard, go figure...).
- SCP Foundation contains SCP-531, an Emo Teen with reality-warping powers constantly in the verge of abolishing Humankind (which is why he's oh-so-very Keter), who unconsciously killed the entire staff at his containment site while mourning his mom's death. He eventually had to be killed by locking him in a glass cage in outer space and blowing it up.
- Potter Puppet Pals had an episode called "Wizard Angst" with Harry going through a Wangsty period. "I'm feeling cranky and pubescent today and I don't know why!"
- In one episode of The Loud House, Lincoln plays a clown at a birthday party for a thirteen year old girl named Maggie. Maggie and her emo friends are unimpressed by Lincoln's childish antics, leading Luan to come and save the party.
- Jimmy Jacobs, who ironically became much more "emo" after he was no longer a teen. When he was a teenager, his main complaints were wrestling the same guys over and over again, not being taken seriously by some promotions, not being paid and dropping out of college. But really, he was mainly an energetic Sissy who wanted to be like Kevin Sullivan, John Nord and The Barbarian, a worrying trio but not exactly "emo". Then BJ Whitmer hit Lacey with Jimmy's rail road spike and he declared himself irredeemable for it, cranking the sissy elements Up to Eleven by painting his nails and wearing excessive eye shadow. He then set out to hijack wrestling shows so he could rant about love, the world and the unfairness of the American healthcare system to the audiences, beginning the Age Of The Fall to help him in this quest.