time
"Knowing that one day you will stand before God, here are some questions you need to consider: How will you explain those times when projects or things were more important to you than people? Who do you need to start spending more time with? What do you need to cut out of your schedule to make that possible? What sacrifices do you need to make?"
The best use of life is love. The best expression of love is time. The best time to love is now."
~ Rick Warren, The Purpose Driven Life, p. 128