"Find a cure. Find a cure for my life." - Ida Maria, Oh My God
Some people call them post-mortems but I prefer the term "Lessons Learned." These are meetings that happen after a project to look at what happened on that project and why. Or something to that effect.
Post-mortems are often used as ways to pass the buck and place blame. To complain about your co-workers or partners. A witch-hunt to find the culprit.
Yuck.
I like Lessons Learned meetings, though. The purpose is to actually get better. Identify ways to improve working together. To acknowledge things outside of our control. To bubble up the real issues that need to be dealt with.
Lessons Learned meetings, when done well, are open forums to discuss ideas and are generally positive conversations that end on a good note. They should happen regularly.
Post-mortems don't happen because the only lesson you learn is to sink down in your chair, attempt to not look anyone in the eye, keep your mouth shut, and/or cover your ass.
They should happen only if, at the end of the inquisition, someone gets blindfolded and placed before an actual firing squad.