Recently (at least for the last 3 years or so) I have seen work and play as being different entities. I have seen workdays as days for work 9 to 5 (or perhaps a bit longer) and weekends as days for play. And on those weekends I've felt very much like I should not be working, like I should be having fun. When, in reality, work and play is all the same thing, it is all life.
If you're not busy and cannot think of anything better to do, why not work in your free time on the weekend and treat is as though it is play?
If I want to work on the weekend in my spare time, I will work!
Quotes:
"I don't think of work as work and play as play. It's all living." - Richard Branson
"This is the real secret of life - to be completely engaged with what you are doing in the here and now. And instead of calling it work, realize it is play." - Alan Watts
