Recently I watched a video by Tom Scott about a Museum of Failure. It's a fascinating video and well worth watching.
Often there is a lot of emphases put on learning from the great successes, seeing what successful people or projects have done and trying to emulate them. But learning from failure is just as important and often overlooked.
Seeing where projects have gone wrong and how to avoid those weaknesses in the future can be incredibly beneficial.
I remember being told once that
You never really understand the value in things like project management and it's easy to see them as needless overhead, until you have worked on a project that has failed.