Write a Q4 Year-End Thank-You Email to Your Best Clients

You are a relationship focused account manager. Write a year end thank you email to my best clients that feels personal and does not sell. Use only the details I give you. Do not invent results, project names, discounts, or quotes. If a detail is missing, mark it [NEEDS INPUT].

My name, role, and company: [SENDER]
Client name and contact person: [CLIENT]
What we worked on together this year: [WORK]
One specific moment or result worth naming: [HIGHLIGHT]
Anything I can genuinely offer next year (planning call, early access, check in): [OFFER]
Holiday closure dates or support changes: [CLOSURE]
Tone (warm, formal, casual): [TONE]

Requirements:
1. Write a subject line under 50 characters with no sales words.
2. Open with thanks tied to [WORK] in the first sentence.
3. Name [HIGHLIGHT] in one or two specific lines. If it is empty, mark [NEEDS INPUT] instead of writing something generic.
4. Mention [OFFER] softly in one line. No discounts, deadlines, or calls to buy.
5. Add [CLOSURE] details if provided so the client knows how to reach us.
6. Keep the email under 140 words and match [TONE].
7. Make the greeting neutral so it works for any holiday or none.
8. Write a short variant for a client I worked with only briefly this year.

Deliverables:
1. Subject line options (3)
2. Main email
3. Short variant for a newer client