"There is no justice. There's just me."
-- Death, "Mort" by Terry Pratchett
"There's no cosmic balance. In the end, everyone dies." -- Death, "The Time of your Life" by Neil Gaiman
A rather depressing pair of quotes, to be sure. But it's important to keep this in perspective: Everybody does something wrong when they're alive. Everybody deserves justice for something someone else has done to them. Most of them don't get it, and those who do are almost never satisfied that justice has been served. The only true justice we can hope for is at life's end, when everyone who's ever wronged us will get what's coming to them, and when we get what's coming to us for wronging others. It's the only thing in life that's truly fair, and deep down, we all know it.
Not surprisingly, every religion on earth has confronted and embraced this in some way or another. The philosophical ones, like Buddhism, tend to view death -- not just death of the body, but the total, final non-existence of the spirit -- as a goal to be achieved. But the deistic ones, like Christianity, tend to see it as a gateway to another world, and it's in that other world that justice is finally served by the weighing of the soul. In other words, some religions claim everyone gets a chance to be justly rewarded in the end, while others say that some get rewarded and some get punished, while atheism basically says that we all get punished through eternal non-life.
We all strive to see some kind of justice served in this world, of course. Civilization wouldn't survive if we didn't. But it's important to keep it all in perspective. Justice is an ideal, and like all ideals it's impossible to find in the real world. We have to settle for the justice we can make, and whether we like how it's served or not, ultimately we have to accept it.
Because the alternative really isn't much of an option.