Dominique Chalvin defines assertiveness as a delicate balance between expressing one’s own personality and respecting others, where it is possible to assert oneself without provoking hostility and to refuse without guilt. This attitude is often summarized by the expression “neither a doormat nor a hedgehog.” In the fields of commerce and marketing, assertiveness is valued in customer interactions, especially when these interactions can be stressful. It proves particularly effective in handling complaints, after-sales service, customer service in bank branches, and insurance claims management.