When the World Goes Post-Apocalyptic, What Happens to Your Average Office Building?

What does the average office building look like when it's been abandoned in a post-apocalyptic world? Does everyone just stop working?<br><br>This is a serious question and not a joke. I know in the Fallout universe, corporations are still a thing but the world is so vastly different there that there's plenty of reasons why people would still work in offices there. But what about other worlds like Mad Max, Fallout 4, Horizon? <br><br>For this let's assume it's been a couple decades at most. The world isn't a barren wasteland. There are some communities and even cities. People are still surviving. But the major corporations are gone or have been severely impacted.