Buyer's remorse is an emotional condition where a person regrets a purchase. It is commonly associated with high-cost items and can be caused by product issues, unrealistic expectations, defects, poor support, or inadequate follow up. While some causes are outside a seller's control, overselling a product or neglecting customer expectations and follow up can also result in buyer's remorse. To prevent it, sellers should set realistic expectations, ensure proper usage understanding, follow up after sales to identify issues, and reinforce the purchase decision.