Time

Time.
Sometimes it flies by like lightning, leaving you behind no matter how you rush to catch up.
Other times, it seems to be caught in a bog, with each moment an agonizing wait between squelches.
At times it is sunk into things of little worth.
Sometimes there isn't enough for all your good works.
Your time is finite, though at times it seems endless.
And take care how you spend it, for you can never exchange the time that you've spent.