In 2010 when Netflix migrated from DVD-by-mail to streaming, from own datacenters to AWS, engineers faced a terrifying truth: in cloud, instances die without warning anytime. Their response defied intuition. Not "fear failure so avoid it" but "intentionally, frequently, during business hours, cause failures and constantly prove the system survives anyway." This birthed Chaos Monkey—randomly killing production instances—and created the field of Chaos Engineering.