Why can I stay focused on useful, mentally demanding content at work, but lose interest after work?

[jbden]

[hoist]

You’re tired; work is unexpectedly exhausting, and after work you just don’t feel like doing anything.

[汪坤健]

Because you’re not very curious about the “useful” information you see at work, you just complete the task.

[I_Love_ZJU (紫金港第一皮革<・)))><<)]

How to keep myself able to read useful things while at work (or school)