Often it is easy to feel we are not important. It is actually in part a good realization, because it has an element of truth. We are important, but not in and of ourselves.
We are important because we are children of the living God. We as people may be children living in obedience to God or children estranged from God, but all mankind is God's children.
For those in Christ we find our importance through being in active fellowship with our Father in heaven through faith in his son Jesus.
For those estranged from God or rejecting God the offer of fellowship is always open. God beckons all who will to draw near and accept the offer of grace offered through Jesus.
Man is great because man bears the image of God and are beckoned by God into eternal fellowship. God wishes for us to enjoy eternity in fellowship with God.