> Build for resiliency and designed to fail safely

This is important, but I'm not sure everybody necessarily agrees on what "fail safely" means.

Fail safely can mean one of:

- It doesn't fail silently

- It doesn't cause cascading failures

- It doesn't cause infinite failure loops

- It doesn't fail in ways that corrupt data

- It doesn't fail in ways you lose money

- You can safely retry

- You can safely retry anytime (not just today, or just this month)