“I love the subject line of this email because it is so unbothered: "Michal, your order is incomplete."”
"Obviously", you tried to make this purchase and pay for it because you wanted this item and we are just letting you know that it is not complete. Based on this, I added the word ‘notice’ to The Sak’s card abandonment emails. In an A/B test, this more transactional style subject line outperformed the existing one with +4% higher open rate and +1% higher click rate.