In EOS, we refer to 90-day goals as Rocks. Why? Picture in front of you a table. On it there is:
A pile of rocks, representing the big things you need to accomplish this quarter
A pile of pebbles, representing your daily tasks
A pile of sand, representing your interruptions every day
A beaker of water, representing everything else
An empty bucket.
If you take the bucket and put the sand in first, followed by the water and the pebbles, the rocks won't fit. Only by putting the rocks in first, then the pebbles (which filter down through the rocks), then the sand and then the water, will everything fit. This is a visual way to say FOCUS ON THE BIG STUFF FIRST! For more look here.