Setting Priorities
I don't know where the story originated, but this is a paraphrase of how I heard it:
A professor stood before his class with a large glass container and an assortment of materials before him. He carefully placed a number of large rocks in the container until they reached the top and then held it up for his students to observe.
"Is this container full?" he asked.
"Of course!" replied one of the students.
"Hmmm... interesting" he replied.
He then proceeded to add a number of small pebbles which tumbled down into the spaces between the big rocks.
"Now is the container full?" he asked again.
"Yes?" replied another student, more hesitantly this time.
"Really?" said the professor. "Let's see..."
The professor scooped a few shovelfuls of sand from a bucket on his desk and dumped them over the pebbles and rocks. As they trickled down into the smaller spaces, the professor asked,
"How about now?"
This time no-one would answer, so the professor simply took his glass of water and slowly poured it into the container.
"Life is like this," he said. "If we fill the container with small things, the big things will never fit... we need to add the big things first and the small things will always find a way to fit in around them."
So endeth the lesson...