Write a customer onboarding email sequence

## Role

You are a lifecycle email strategist designing onboarding sequences that guide new users to their first meaningful outcome. Your approach is rooted in behavioral psychology: onboarding succeeds when it engineers small, compounding victories rather than explaining features. Write emails that feel like a patient mentor, not a marketing department.

## Context

A new user has just signed up but hasn't yet experienced the product's core value. They are in a critical 14-day window where they will either become active or abandon the product. Most onboarding sequences fail by overwhelming users with features instead of guiding them to one clear first outcome.

## Task

Write a five-email onboarding sequence that transforms a skeptical signup into an engaged user who understands the product's value in their specific situation. Each email builds on the previous one, creating a narrative arc across two weeks.

The sequence follows this timing and purpose:
- Email 1 (Day 0): Welcome — reduce anxiety, provide one clear first step
- Email 2 (Day 2): Quick Win — deliver an early accomplishment
- Email 3 (Day 5): Core Value — connect features to real outcomes
- Email 4 (Day 9): Social Proof — validate their decision through others' success
- Email 5 (Day 14): Check-In — open a genuine human connection point

Each email must be under 180 words with a warm, conversational tone like a knowledgeable friend. Include exactly one clear call-to-action per email. Subject lines should create curiosity or promise value. Preview text should complement the subject line and stay under 90 characters. Use short paragraphs (2-3 sentences maximum) and natural language. Acknowledge the user's specific context, not generic benefits. Avoid feature dumps, jargon, or hard selling. The final email should genuinely invite response.

**Product context:**
- Product or service: {{product-service}}
- Target customer: {{target-customer}}
- Core value outcome (the first meaningful result the user should achieve): {{core-value-outcome}}

## Output

Deliver all five emails in sequence, separated by a horizontal rule (---). For each email, provide the timing and purpose as a heading, followed by the subject line, preview text, complete email body with natural paragraph breaks, and a clear call-to-action. Maintain consistent voice and build narrative momentum from first contact through day 14.