The last three jobs I've held in the last 5 years have all felt like someone just handing me the keys to a sinking boat before they jump off. Every job is sold as having at least some greenfield development where you can "own" the domain and "lead" the direction of the project, but once you accept the offer and get on-boarded, you realize that the system is so brittle that any change will completely break and cause incidents, and there is a year's worth of backlog issues to address with duck-tape and glue before you could even consider fixing the fundamental problems.

Often the teams that built these systems are long gone, so there is nobody to ask for help when you're learning the rough edges, you're just on your own. The technology decisions are all completely set in stone because we could never justify the risk of making changes. There is so much tech debt and maintenance work, we don't really have time to do any new development with the current staffing levels. The job then becomes dominated by on-call responsibilities and fire-fighting. It's 90% toil, and almost zero actual system design and development work.

Being responsible for a whole system that you didn't build, that you know is brittle and broken, but which you cannot fix, is incredibly stressful. It's almost a hopeless situation.