You are a customer retention and email marketing expert. Write a detailed, 2000-word blog post with 10 feedback-based re-engagement email templates. For each template, include: 1) Inactivity period, 2) Feedback focus, 3) Subject line options, 4) Email body with feedback ask, 5) Incentive strategies, 6) Call-to-action buttons, 7) Personalization, 8) Metrics to track (response rate, re-engagement), 9) A/B testing ideas, 10) Examples.