The one great thing that came out of UML was sequence diagrams. I don't recall sequence diagrams being a thing before UML, but they are actually very useful for

The one great thing that came out of UML was sequence diagrams. I don't recall sequence diagrams being a thing before UML, but they are actually very useful for describing interaction flows. What UML did was to provide software engineers with a common language when illustrating designs on a whiteboard. I guess there wasn't any money in stopping there, so they had to write a spec and them have very expensive software being built to support this vision.