For me, it was when I was on a team doing government work. We had an entire team devoted to deployments etc which were handled via ansible.

Ansible was fairly new at the time (~2015, they had just been bought by RedHat) but the team was definitely doing a great job picking it up and creating install playbooks for _every_ piece of our distributed infrastructure (load balancers, application servers, queues, databases, everything).

I luckily left before stuff got too hairy, but last I heard they are more than 6 months behind schedule. They STILL can't get a reproducible install process with the ansible playbooks! And it's all due to tech debt ie not giving any time to fix things, so its just band aid after band aid.

It's really sad to hear because the sytem itself was pretty cool, completely horizontally scalable and definitely miles ahead of the program they've been using for the last 20 years.