Actually, what I learned is that being afraid to deploy on Friday means you're lacking in testing, verification, auto healing and rollback processes.
Also, if something goes down in a way that requires a human to work on the weekend, it should result in a postmortem, and all of the components in the deployment chain related to the failure should be evaluated, with new tasks to fix their causes. If it happens multiple times, all project work should stop until it's fixed.
This of course is balanced against how much failure your business can tolerate. If the service goes down and nobody loses money, do you really need your engineers working overtime to fix it?
Also, if something goes down in a way that requires a human to work on the weekend, it should result in a postmortem, and all of the components in the deployment chain related to the failure should be evaluated, with new tasks to fix their causes. If it happens multiple times, all project work should stop until it's fixed.
This of course is balanced against how much failure your business can tolerate. If the service goes down and nobody loses money, do you really need your engineers working overtime to fix it?