Human Pride gets in the way....the need to feel significant somehow....to die to ones self achievements is hard for most....harder still for those who have a church which requires they levels of achievement.
To accept the "finished work of Christ' in entirety means one can see the depravity of man in himself....that usually only occurs the closer we become to Christ in our relationship with him....the more we see Him for He he is... the more we also see how far from His righteousness we are.....but the more grateful we are and greater love for Him we have for seeing there really isn't anything in us worthy....
... But because He stepped in front of us...bearing the guilt and shame...and the death sentence for us...we are truly forgiven....and His Resurrection evidenced death is swallowed up in Victory .....So that..." NOW there is no longer ANY condemnation to them who are in Christ Jesus."
Finished....Indeed!...otherwise...defeated and lost...
I've often thought of works based salvation as if we are drowning in a stormy sea,a helicopter hovers over us to lift us up,the only requirement on our behalf is that we must first be dry.