So if that's how God sees our righteous acts... I don't want to even know how He would refer to all the acts that we would not call 'righteous'! So if the acts here on earth that we might call 'righteous' or 'good' are that far from His standard, it is pretty clear that we can never satisfy the requirement of being 'Holy' in God's sight.
So switching gears a bit...it is tax season (Boo, Hiss...), and it might be good to use an example that resonates around this time of year. Let's say, just as an example, that in 2014 you gave $5,000 towards 'charitable contributions' (e.g. Church, Goodwill, etc.). We might consider that a 'good' or a 'righteous' act (and believe me, I'm not saying it's not a great thing to do).
In comparison, God gave His perfect Son - to step down from His Throne, be born into this messed up world, live a sinless life, so He could eventually be tortured, mocked, and killed for the sins of others (you, me, us). THAT meets God's standard for a GOOD and RIGHTEOUS act.
And if those were my options... I'll take 'charitable contributions' for $5,000 please, Alex! I mean, seriously, I have a son, and I can't imagine ever even considering the thought of allowing him to die for the best of you (let alone the rest of you)!
God knows we can never reach His standard of Holiness on our own. That is exactly why He planned to send Jesus to us, so He could be born into this world - born of a woman, as a human Himself. So He could live a sinless life and be the Perfect Sacrifice...for He was, is and will always be Holy... for He was, is and forever will be God. Only a perfect, spotless, sinless sacrifice could be used to take another's sin. If I am sinful and I die for that sin, it's my own sin that is atoned for, not yours or anyone else's... only One who is without sin can take on another's punishment.
Isaiah 53:5-6 says it pretty clearly (and was prophetically written over 700 years before it happened):
5 But he was pierced for our rebellion,
crushed for our sins.
He was beaten so we could be whole.
He was whipped so we could be healed.
6 All of us, like sheep, have strayed away.
We have left God’s paths to follow our own.
Yet the Lord laid on him
the sins of us all.