Over at Daylight Atheism, Ebonmuse discusses the “just world” hypothesis:

[P]eople are uncomfortable believing that suffering is random, that sometimes bad things happen for no reason at all. Instead, we prefer to believe that people must have done something to deserve what they get. This is obviously a reassuring and comforting belief, which explains its wide appeal. (If bad things only happen to those who deserve it, and I’m a good person, then I can be sure that nothing bad will happen to me.) Belief in the just world can be thought of as a failure to apply the null hypothesis in the moral domain: rejecting the explanation of chance, we prefer to believe that everything that happens is deserved. But the problem is that, however much we’d prefer to believe otherwise, the world is random and sometimes bad things do happen for no reason. And because it encourages us to look down on victims of misfortune as deserving their fate, the just world hypothesis usually leads to worse injustices.

Lots more on the history and consequences of believing the “just world” hypothesis at Daylight Atheism.