The book of Ecclesiastes has many layers. It describes the lives of people under the sun who are cut off from God. To that extent, life is vain and a grasping for the wind. In addition, when Solomon addresses the reader DIRECTLY, he is not talking about people who have turned away from God and who refuse to submit to God. It is important to see the distinction.
How are we supposed to prepare at all times? How are we to live our days and how important is prayer? What should we pray for? Are we ready if Christ were to come back tomorrow? Are we worthy enough? Is God our first priority and can we trust Him to take care of ANY situation that we are faced with? Do we truly understand how important God is in our lives and if we shut Him out, what would the consequences be?