During my Computer Science studies, one of the topics we learned about were the various conditions that can contribute to a computing process becoming deadlocked. One such condition is known as a circular wait:
"Circular wait: each process must be waiting for a resource which is being held by another process, which in turn is waiting for the first process to release the resource."
Recently it became clear to me that groups of people can exhibit this behaviour also, when each person is waiting for the others to take action, when in fact none of them are acting:
Bob is waiting on Harry → Harry is waiting on Mary → Mary is waiting on Bob...
Just like an observer of a computing process, it takes an observer from outside of a process to identify the deadlock, and step in to unlock it. This is when a leader needs to step in and assign direct actions to someone, to ensure that at least one person is accountable for the process being completed successfully.
Without such oversight, bizarrely, a process can simply stop.