The subject line is the first thing a customer sees and plays a crucial role in open rates. Effective subject lines for cart abandonment emails are often: - Personalized: Use the customer's name or reference their specific cart items. - Urgent: Create a sense of urgency (e.g., "Your Cart is Waiting!", "Don’t Miss Out!"). - Curious: Pique interest (e.g., "Forgot something?", "Your Items Are Going Fast!").