If someone wears pajamas to a formal event, which type of social norm are they most likely violating?

When someone wears pajamas to a formal event, they are likely violating a type of social norm known as a dress code. Dress codes are unwritten rules about what is considered appropriate clothing for different occasions. For formal events, people usually expect others to wear suits, dresses, or other elegant attire, which helps create a specific atmosphere. By wearing pajamas, the person not only goes against these expectations but may also make others feel uncomfortable or out of place. For example, if everyone else is dressed in formal wear for a wedding, wearing pajamas would clearly stand out and disrupt the social expectations of that special occasion.