Am I my neighbor's keeper?

It doesn't take long after sin enters the world for its effects to show. After Adam and Eve are expelled from the garden, Cain is overtaken with jealousy towards his brother, Abel. Cain allows sin to master him, despite God's explicit warning, and he murders Abel. When God asks Cain where Abel is, Cain's famous response is, "Am I my brother's keeper?" But perhaps being your "brother's keeper" is critical to living in a way that fits with how God wants society to look. Christ affirms that the second-greatest (or is it second, greatest?) command is to "love your neighbor as yourself," and gives a broad definition of "neighbor" in the parable of the Good Samaritan. Not only are we our brothers' keepers, but we are also responsible to be neighbors to many others who cross our paths.

Plantinga points out that there are two ways of sinning towards our neighbors in two chapters labelled "Attack" and "Flight." The attack side seems prominent in James 2:8-13

8If you really fulfill the royal law according to the Scripture, "You shall love your neighbor as yourself," you are doing well. 9But if you show partiality, you are committing sin and are convicted by the law as transgressors. 10For whoever keeps the whole law but fails in one point has become accountable for all of it. 11For he who said, "Do not commit adultery," also said, "Do not murder." If you do not commit adultery but do murder, you have become a transgressor of the law. 12So speak and so act as those who are to be judged under the law of liberty. 13For judgment is without mercy to one who has shown no mercy. Mercy triumphs over judgment.

It's not too difficult to see that active partiality, adultery, murder, as well as other actions like gossip, lies and slander and the expression of attitudes like envy, jealousy and bitterness SCREW THINGS UP. To please God, we must not do these things.
But many people use the fact that they don't do these things to argue that they are good people, who are far enough away from the evil end of the scale that God must be pleased with them, and surely couldn't be angry. Is there something more to loving your neighbor? Plantinga explains in the next chapter how "Flight" disrupts shalom. When we are apathetic, or when we intentionally avoid or ignore situations where people are suffering from the consequences of sin, we're still in violation of the great command to love our neighbors. James hits on this concept as well on the next section of the papyrus:

14What good is it, my brothers, if someone says he has faith but does not have works? Can that faith save him? 15 If a brother or sister is poorly clothed and lacking in daily food, 16 and one of you says to them, "Go in peace, be warmed and filled," without giving them the things needed for the body, what good is that? 17So also faith by itself, if it does not have works, is dead.

What does this mean for me and my neighbors? Does it mean that I should interrupt a peaceful evening walk on my day off to go see why those kids in the park are yelling and waving sticks at each other? Does it mean that when a teenager is breaking a glass bottle on the steps of the elementary school I should stop her and bring a broom so she can clean it up? Does it mean I can't just shake my head and condemn society because so many fathers neglect their kids, but I should take the time to be a male role model to a single mother's son? Does it mean I can't just bemoan how parents don't care about their kids education, so the kids fail, but I should take the time to ask a kid how school is going, volunteer to do tutoring, and take them out for ice cream when they get a good report card? Please give me more examples in your comments, my insightful readers. What do we complain about and do nothing about when it comes to the welfare of our neighbors?