Have you lived a perfect life – nothing you have done has been wrong? Do you know anyone who has never done or thought anything bad? The answer to both questions must be NO, unless one is very deluded.
You see the problem is that God made man as a perfect being, but man disobeyed God and since then we all follow in the same footsteps. An insurmountable barrier now exists between God and us. He requires absolute perfection, so we all fall short of the mark.
So even if we feel we lead a good life, better than many people in fact, and do many good and worthy deeds, this doesn’t tip the scales in our favour. God tells us in the Bible: "There is no one righteous, no not one" (Romans 3:10) and "All our righteousnesses are as filthy rags" (Isaiah 53:6). So we can't even earn ourselves points with God for our good deeds.