Software engineering concerns: coupling

Back in the dark ages, prior to the collapse of the Soviet Union, we used to care about software engineering concerns, such as the degree of coupling "between modules". What that even means, in this day, is a contentious issue, but I found my self successfully arguing about coupling a few weeks ago. A move that was motivated by tidiness lumped some code that had been separate into a common jar file. Now, unrelated modules were suddenly tightly coupled. I can't describe the circumstances, but that coupling recently created a nasty problem, due to the need to not deploy the latest version of one component, while the others needed to be deployed. The tight coupling that had been unwittingly created caused otherwise unnecessary pain.