Working at scale is truly a different ball game. A 1% yearly failure rate from a service serving around 1m users (a sizable but not huge number in today's age)

Working at scale is truly a different ball game. A 1% yearly failure rate from a service serving around 1m users (a sizable but not huge number in today's age) will end up failing for 1000 different users on average. If the service is responsible for something like payments then 1000 different customers probably will end up calling support, support will have to identify and handle this anticipated failure mode, etc.. Sure error handling strategies like exponential backoff and microservice paradigms like "sagas" try to teach us more error-avoidant approaches, but sometimes it can be a lot to handle.