Ecclesiastes 2:17 says, Therefore I hated life; because the work that is wrought under the sun is grievous unto me: for all is vanity and vexation of spirit.  Solomon seemingly had it all, but nothing brought satisfaction.  Wisdom didn't, nor did his works.  When we look at our lives, we may feel that if we can just learn a little more, or accomplish a little more, that we will finally have fulfilled our purpose.  Solomon found this not to be true, and so will we.  Verse eighteen says, Yea, I hated all my labour which I had taken under the sun: because I should leave it unto the man that shall be after me.  Solomon hated the business of this world, which was his labor under the sun.  Whatever he accomplished was going to be left to another to care for or benefit from.  The same is true today.  We realize that whatever we accomplish or attain in this life is going to be left to another, or at the return of Christ, just left period.  We should not allow the things of this world to cause us to feel frustrated.  All things under the sun, or of this world as we would say, are temporary. In verse nineteen Solomon continues,  And who knoweth whether he shall be a wise man or a fool? yet shall he have rule over all my labour wherein I have laboured, and wherein I have shewed myself wise under the sun. This is also vanity.   Solomon said he had no way of knowing how those that would benefit from his labor would use what he had acquired.  That much we can be sure of.  The things of this world are no longer ours once we die.  If we are looking to them to bring everlasting purpose to life, we are going to be disappointed.  We may be happy to leave a lot to our children, but if everything we worked for was of the world and not for God's kingdom, we will be disappointed, and so will they if they do the same.  Verse twenty says, Therefore I went about to cause my heart to despair of all the labour which I took under the sun. Solomon was very unhappy in his quest for purpose in life, and so will we be if we look to the things of the world for happiness without following God's plan for our life.