What are the best "Get started with..." dev guides? Did any of them leave you a mental "afterimage" (you can't forget them) ever?

For example:

- Stripe: Get started: https://stripe.com/docs/development/get-started

- Vercel: Get started: https://vercel.com/docs/getting-started-with-vercel

- Supabase: Get started: https://supabase.com/docs/guides/getting-started

These are just some examples, not necessarily the best, definitely good enough!

What about you? What can you not UNSEE because it was so good?