Smile! Sotamura-sanA 4-koma manga about a tall girl who's (wrongly) perceived as a delinquent largely because her face seems fixed in a perpetual scowl and the friend who tries to help her improve her image by teaching her how to smile.
This manga contains examples of:
Accidental Innuendo, non-sexual variation: poor Sotomura is so bad with words she can make the most innocent phone call sound like a crime boss giving veiled commands to his minions. Her plan for her little brother's surprise birthday party reads like an assassination plot. And the less said about her brief experiment with Twitter the better.
A-Cup Angst: Her classmates are convinced she binds her breasts. Oh how she wishes this were true.
Always in Class One: Averted. Sotomura and Haruno are in separate classes, so no one in Sotomura's class gets to see how normal she acts with her only friend.
Big Sister Bully: Sotomura's little brother's friends are convinced she bullies him. She adores him and he does all those things she "forces" him to do voluntarily because he adores her in return.
Cannot Tell a Joke: When Sotomura tries to tell a joke, people think she's serious and get scared of her.
Can't Get Away With Nothing: Sotomura's classmates interpret everything she says and does as "proof" of her delinquency. That subtly threatening phone call? She was just asking her little brother to tape her favorite anime. Those scrapes, scratches and Clothing Damage that "prove" her fighting prowess? She got them rescuing a kitten from a tree.
Delinquents: Sotomura is wrongfully believed to be one. Back in her days as a student, her mother really was one.
Face of a Thug: Sotomura is feared by all, primarily because she can't seem to smile without somehow looking like she's about to shank you. The plethora of misunderstandings that follow her around don't help, either.
Her hair is (naturally) brown, she wears her uniform skirt long (because she's extremely self-conscious about her height) and refuses to wear the bow (because she thinks it draws attention to her flat chest). All are considered delinquent fashion statements.
Failure Is the Only Option: All of Sotomura-san's attempts to make friends backfire, in large part because she's so socially awkward and bad with words she keeps unintentionally reinforcing her delinquent image. In contrast, Himeki's attempts at delinquency and imperfection (even when failing tests deliberately).
Huge Schoolgirl: Sotomura-san. She's so self-conscious about it that she leans down to speak to most people - combined with her unnatural grin, she tends to lose terrifying. Unfortunately, even when she maintains good posture it frightens people, so she can't win.
Not Blood Siblings: Sotomura and her little brother are, but most people who see them together are convinced they're not and that he's just an underling.
Not So Different (oblivious example): Himeki-san, the Spoiled Sweet girl who wants to be a delinquent just like Sotomura-san has no idea that Sotomura is actually just as sweet as she is.
Oblivious to Love: Due to the aforementioned issue with her struggling to find friends in the first place, Sotomura doesn't realise Mikumo may want to venture into romantic territory.
Older Than They Look: Sotomura's mother looks so young people at first think she's Sotomura's elder sister.
Shrinking Violet: Again, Sotomura's true nature in all but appearance. She's even afraid of elevators. Unfortunately, people misinterpret her fear as anger. Mikumo is impressed by her bravery when she rides an extreme roller coaster twice, when in reality she was too paralyzed by fear to get off the ride.
Spoiled Sweet: Himeki, the rich girl who wants to be a delinquent just like Sotomura...if only her absurdly sweet nature didn't keep getting in the way.
Sure, Let's Go with That: Sotomura's self-proclaimed underling once asked Sotomura where she could buy Sarashi to bind her chest. When Sotomura asked why she's being asked that, the girl said she believes that's what Sotomura does. Sotomura decided to allow the girl to believe that.
The Unsmile: One third of the reason people misunderstand her - her forced smiles aren't inviting.
When She Smiles: Sotomura's normal smile is quite pleasant, but it only shows when she's not self-conscious. As mentioned above, most of her problem come when she tries to force it.
The Woobie: Sotomura-san, so much. When two girls mistake her for a ghost, she's devastated at being called scary.