Basic Trope: A guy is never seen with a shirt on and bares his chest everywhere.
Straight: Jacob almost never wears a shirt.
Exaggerated: Jacob NEVER wears a shirt, period.
Downplayed: Jacob wears some sort of coat, cape, sash, or other garment that covers up most of his torso, but doesn't wear an actual shirt.
Jacob lives in a hot climate, where not wearing shirts are normal.
Jacob is a Nature Hero and wears only enough clothes to keep from being arrested.
Inverted: Jacob never takes his shirt off, even in situations where it doesn't make sense to keep it on.
Subverted: Jacob is shirtless for the whole summer. However, in the fall, someone buys him a nice shirt. He likes it so much that he wore it for the rest of the year.
...until someone steals it.
Normally bare-chested Jacob has to wear a T-shirt... but nothing says that it couldn't be transparent from the front.
Jacob is allergic to fabric, and breaks into a rash if his chest is ever covered by a piece of clothing.
Jacob doesn't know how to put on a shirt.
Instead of Jacob, Jane is the one who doesn't EVER bother covering her chest, for one reason or another.
Jacob has multiple personality disorder. Therefore, he may be modest one day, and not wear a shirt the next. sometimes an open shirt, and sometimes just a sash.
Jacob has a double life. During the day, he is shirted. At night, he is a shirtless crimefighting vigilante.
Jacob is normally bare-chested whether he wears a shirt or not; but then comes a time when he has to walk around in cold enough weather that he's thus forced to wear a long-sleeved shirt and close it at all times, lest he suffer pneumonia; and true to himself, he keeps grumbling about how he hates his situation. Eventually, he does return to his usual wardrobe of choice, only to later have to disguise himself as Alex, who never goes shirtless in public. And just when Jacob finally ditches the disguise, he gets invited to a close friend's wedding, and decides to not embarrass him/her by walking around with a naked torso. But just when things finally seem to return to normality, he has to wear a hazmat suit because there's been a leakage of a bio-chemical warfare agent in the neighborhood, which is highly transmissible via skin contact ... At this point, he gives the middle finger to the universe and wears a specially-designed hazmat suit whose torso is transparent!
Averted: Jacob always keeps his shirt on in public.
Enforced: "Hey, this guy has an awesome physique. Let's show it off more and attract some female fans!"
Lampshaded: "Do you notice that you never see Jacob wear a shirt? Must be for the girls.".
Invoked: Jacob decides to start going around without a shirt because he thinks it'll make him look more badass.
Jacob decides to put a shirt on(because it's cold)...but not before greeting a few girls.
A terroist notices everyone has bulletproof armor on...but he knows at least one person is being a rebel. After all, this is a Stoner Flick!
Defied: To avoid attracting unwanted attention, Jacob attempts to wear a shirt at all times.
Discussed: "If Jacob went around without a shirt on, chicks would be all over him".
Conversed: "Couldn't Jacob wear a shirt at least once? He's making me sensitive about my appearance".
Jacob's shirtlessness causes a cultural clash in some towns and areas that have more modesty.
Jacob gets easily injured in a gunfight/swordfight.
Reconstructed: Jacob doesn't care because he likes going shirtless too much.