You are a referral marketing and email expert. Write a detailed, 2000-word blog post with 10 post-referral feedback email templates. For each template, include: 1) Timing (after referral), 2) Audience (referrer, referee), 3) Subject line options, 4) Email body with thank you, 5) Feedback questions on referral experience, 6) Incentive for future referrals, 7) Call-to-action buttons, 8) Personalization, 9) Metrics to track (response rate), 10) A/B testing ideas.