So often, we are tempted to quantify goodness on a continuous scale where some neighbors are better than others (and where we are typically better than all our neighbors).
Suppose we rate the percentage of the time that someone lives a truly unselfish life as the variable of interest. Then a comparison of 5 people in your neighborhood might look something like this...
If God grades on a curve, we are tempted to say that person B is a "good" person, person C is "pretty good", person D and E are "Ok", and maybe person A is "selfish".
However, the trouble comes when we realize there's a perfect, cosmic judge in heaven, whose yardstick for righteousness is perfection. The only person to meet this standard was God's son sent for us, Jesus Christ. When we put the above numbers up against Jesus Christ, we get an entirely different picture...
Clearly in this light, righteousness is an all-or-nothing proposition. We all fall short and our petty attempts to be good amount to nothing in the eyes of an all-knowing, all-seeing God. The only way we are going to pass His Standard is if we get to work in a group with Jesus (where Jesus is that straight A student who does all the work and we skate by on his merit).
This is a gross simplification of the concept of the depravity of man, but hopefully a clear one. The standard is not your neighbor, but the standard is Jesus Christ. Unless you appeal to that higher power, you are not going to get into heaven on your own righteousness.