According to hat etiquette and social norms, there are some common situations where a lady may choose to remove her hat indoors, such as in homes, restaurants, or theatres. It can interfere with interactions or views of others. During meals in formal settings or events for better etiquette. When singing national anthems as a sign of respect. In certain religious ceremonies, depending on the traditions. For inconvenience or, if requested, due to tight spaces. However, rules vary in different cultures.