Have you ever had a boring job? Some jobs have a great deal of downtime without a lot of busy work. That sort of scenario can lead to boredom, and a sense that the hands of time are creeping along at a snail's pace. David was a shepherd boy with a lot of time on his hands, surrounded by animals that were unable to converse.
What do you do with downtime, when there is no one to talk with? Or what did you do before you had an iPhone, and earbuds, with music to ...play? Imagine having no technology in the outdoors with shifting weather patterns. I am not sure what you would do in such a situation, but the young shepherd boy used this time to talk with God, sing praises, and fend off potential threats to his fur-ball friends. What can we learn from his example?