[nikau]

This sounds more like you don't have other fulfilling hobbies to focus on once work finishes for the day, or management is pushing for results so hard that you feel like you need to work off the clock.

The only time I sometimes think of work outside business hours is on bike rides because its otherwise not very mentally stimulating.

[LouisSayers]

It depends on the work. If you're writing a CRUD app then sure, it's easy to check out.

If you're building out new infrastructure, doing a huge refactor or stuck on a tricky problem then anyone that naturally cares about their work will have ideas moving around in their subconscious.

For me personally, I'm building my own software, so my asshole boss likes to push as hard as he can :D