There were many subjects for these PSAs -- don't waste electricity, don't litter, don't take government issued pens home from work, don't incinerate yourself by using too much lighter fluid on the grill. And of course the ever popular OpSec -- don't say anything related to military operations where people can hear. These weren't just aimed at soldiers. Dependents were expected to keep their mouths shut too, and these PSAs ran during Sesame Street and Scooby-Doo just as much as Cheers and Falcon Crest.
Sadly(?) only a few of the ads from the '80s, when I was growing up, are on YouTube, but there are plenty of modern versions available. They're highly informative and should be viewed by anyone who comes out of the civilian world with no knowledge of basic information security.
Not that I have anyone in mind.