Wall Glower

Our characters are socializing happily. They're eating, drinking, gossiping and so on. If the scene goes on for too long, you might wonder what the point is. Until the camera pulls back and we see a single character who's somehow alienated from the others, watching them with some combination of sadness and resentment.

This should be distinguished from situations where the character has to do some chore and is prevented from joining in the fun. Someone doing a Wall Glower could easily walk right in, but for one reason or another they don't want to. Presumably, they're hanging around only out of masochism. They usually storm off after a while anyway.

It's "glower" as in "angry stare", pronounced to rhyme with "flower", by the way.

Anime and Manga

 * Matt (or Yamato) from Digimon tends to do this a lot. mostly with his harmonica.
 * Lucy from Elfen Lied is all about this trope. Considering how she was abandoned and had to live at a horrible Orphanage of Fear when she was younger where she was regularly harassed/bullied by the other kids. And that's not even the half of it.
 * In the early part of Full Metal Panic!!, No Social Skills Sousuke tended to end up as the glowerer in these situations when they involved Kaname... Mostly because it was his job to stalk her and the others are blissfully unaware that he is nearby.
 * Or sometimes everyone else is aware other than the target he's supposed to be protecting (normally Kaname or Tessa)... thereby discouraging any potential assassins from getting close to them. Of course, this tends to just have the effect of isolating them. He means well, anyways.
 * Every scene in Black Jack that takes place in a karaoke bar or similar setting involves the title character quietly seething at the table.
 * Naruto: Definitely Naruto and Gaara used to do this quite frequently, but it is likely that this applies to most of the Jinchuriki.
 * This even applies to the filler-character Sora, who's a pseudo-jinchuriki.
 * Vegeta. Any time he's included in any sort of party scene, and there's no food involved, he will be doing this.

Comic Books

 * This is lampshaded in Captain Britain and MI:13 when someone calls out Blade for standing against a wall with his arms crossed and sunglasses on not speaking to anyone, during a party. After a tense moment he takes off the glasses and apologizes, saying that he'd been hanging out with superheroes too much, and starts socializing.

Film

 * Subversion in the film Back to The Future, during the big prom scene. The camera pans past several dancing teenage couples and eventually settles on George McFly off to the side, very much alone—except that he's dancing and having a good old time all by himself. (not to mention he's thinking about Marty's scheme)
 * Scott Pilgrim vs. the World: Stevie enthusiastically tells the rest of the band how awesome he thinks they will be. He walks away from the window the exact moment he says "We need stalkers", revealing the face of Knives Chau (Scott's ex girlfriend) tearfully looking at Scott (who is sitting next to Ramona, his current girlfriend), complete with scary music and snap zooms on her face that will fit snugly in a Japanese horror movie.
 * Serenity: Rare humourous example: after a Sexy Discretion Shot for Simon and Kaylee, we see River looking down from the ceiling (hopefully more to figure out what they're doing rather than the Unfortunate Implications of jealousy), making this the one and only Wall Glauer.
 * *groan*
 * Yes! YEEEAAAAAHHHHH!
 * In Sweeney Todd: The Demon Barber of Fleet Street, Sweeney Todd gets three wall glowers in a row during the song "By the Sea" to hilarious effect.
 * In a cut scene of the movie version of Battle Royale, the class's team has won a basketball game and everyone's running onto the court cheering them on. In the back is Mitsuko, who actually looks like she wants to join in for a second. She doesn't and just walks away.

Literature

 * Severus Snape attempts to do this during Slughorn's party in Harry Potter and the Half-Blood Prince, however he is thwarted when the following occurs: '... Slughorn threw out an arm and seemed to scoop Snape out of thin air. “Stop skulking and come and join us, Severus!” hiccuped Slughorn happily.'
 * Jane Austen has a few heroes—Mr. Darcy from Pride and Prejudice and Mr. Knightley from Emma—who prefer the wall to the dance floor at a ball, unless it's with that very special someone.
 * Jane Eyre pretty much has to do this when Mr. Rochester instructs her to come down to the party every night while Blanche and co. are at Thornfield.

Live Action TV

 * How I Met Your Mother: The whole gang are hanging out at the bar — except Lily, who's had a nasty breakup with her fiancé. The camera pans up, and there she is, staring in the window.
 * ER: Most of the first-season characters are dining at the local greasy spoon. We go to an exterior shot and sitting in her car, staring bleakly out is Susan Lewis, who ends up driving away.
 * Buffy the Vampire Slayer: An all-vampire version featuring Spike, who can't attack people anymore.
 * In the Babylon 5 episode "The Paragon of Animals", Lyta Alexander is shown standing outside a triumphant meeting of the new Interstellar Alliance, emphasizing the outsider status of Lyta personally and telepaths generally.
 * In one episode of Boy Meets World, Shawn stands outside the college coffeehouse looking on sadly as Cory, Topanga and the rest of their friends sit around laughing and talking about how many kids they each want to have.
 * Dr. House has been known to do this.
 * Chuck Bass did this on the second season finale of Gossip Girl.

Professional Wrestling

 * At Wrestlemania X, after Bret Hart had won the WWF World Title, all the faces came to the ring, lifted him on their shoulders and celebrated. In the entrance aisle was his brother, who'd beaten him in the first match of the night, doing this and saying 'what about me?'

Video Games

 * In Final Fantasy IX, all the characters gather round a table for a meeting...except The Stoic Amarant, who is leaning against the wall with his arms folded.
 * In a scene from Advance Wars: Dual Strike, the Allied Forces COs are all celebrating the victory in their own particular way—Grimm and Max are eating Saiyanesque piles of food, Javier is hitting on Jess, Jess is dragging Lash to the table by her ear to teach her proper table manners... but Hawke, who recently pulled a Heel Face Turn, is standing outside, because he believes that the warmth and festivities aren't deserved by one as stained by blood as he... until Jake comes out and drags him inside.
 * During any social event or even team meeting in Chrono Trigger, bonus party member stands apart from the main group and will not contribute unless called upon.
 * Final Fantasy VIII has a big dress party celebrating the promotion of new SeeDs at the beginning. Guess how Squall handles the situation.

Western Animation

 * The Cheers spoof in The Simpsons episode "Flaming Moe" includes one of these with Homer standing outside looking through the window.

Web Original

 * Dr. Horrible's Sing-Along Blog: Dr. Horrible looking in at the beginning of Act II.