Especially when your employer watches your every move every second you're in their building. Cameras, remote desktops on every PC, services that track what files you open and when, keyloggers, et cetera. Not having enough work in such a paranoid environment where you get griped at for doing anything outside of your responsibilities or for not being in the building exactly eight hours a day can be a living hell.
I'm in a situation like that currently, but in an open plan office, with a manager sitting behind me keeping me in line.
And since our bug tracker is linked to timesheets, things like refactoring don't happen anymore, unless linked to a specific feature/bug (developers can't create these). The nett effect is that things that used to take me 2 hours now take 8 hours, so I can fill the day. Parkinson's law is not a joke.
But the opposite is true, too.