TIME

We all waste time.  We shouldn't . . . it's very valuable . . . but we do.  The old you get the more you realize this. 

Well, how do you waste your time?  What do you do when you just don't feel like doing anything?  Whatever it is, I bet you can justify in your own mind that it has some value.  Does it really?  Think about it.  We are always doing something.  Some thing are just more valuable than others.  Do what has the MOST value.
:-)