You and me are "knowledge workers", that means we "process information" into value added knowledge, processes, software, designs, you name it.
One thing that we are probably not so aware of is that time is limited and should not be used for work at all unless really needed. In fact, Time is the knowledge worker's inventory (in Lean terms), which means that if we use too much of it we are in effect hiding innefective ways of working, i.e. waste.
What do I mean with this? Simple, if you are working more than the 7,5 (in Finland) or 8 hours/day (elsewhere) required by law, then you must ask yourself: what could I do so that I could accomplish the same amount of valuable work without working more that the limit/day?
Chances are that what you do can be very much improved with simple tricks, but the important thing here is: if you find yourself using more that the 7,5/8 hours/day you have to stop, really stop, and use your precious time thinking how you can do the same in less hours. You owe it to yourself! Be Better!