This study examined how regret—an internal conflict arising from consumers' failure to bring coupons—affects consumer purchasing behavior. Regret can be classified by its timing of occurrence into anticipated regret (before purchase) and experienced regret (after purchase). Through two research models, this study derived the antecedent and consequent variables of both anticipated regret and experienced regret. The findings revealed that coupon proneness and the perceived benefit of coupons influence the occurrence of regret resulting from not having a coupon. Additionally, consumers who anticipated regret were found to lower their purchase intention for alternatives for which they had not prepared a coupon and to increase their intention to postpone the purchase of such products to a future occasion. Meanwhile, experienced regret arising after purchase was found to negatively affect consumer satisfaction and to increase future coupon usage intention, confirming that consumers engage in volitional behavior aimed at avoiding such regret experiences in future purchases. Furthermore, it was empirically confirmed that consumer satisfaction and coupon usage intention ultimately affect repurchase intention.