Disasters I don’t care about

I have recently lost very little sleep over Haiti, and started wondering why. Over the years, there have been certain tragedies that for some reason have electrified me – the Oklahoma City bombing, the Dunblane massacre, the Beslan hostage crisis and the Indian Ocean tsunami, to name a few – and others that have completely failed to divert me from household chores.
Why? I don’t have the faintest idea. I can’t see a pattern. Maybe it’s timing, that I was at a certain emotional place when the stories broke? Maybe it's the storytelling itself, that a very good reporter told it to me first? Maybe I have been unevenly distracted by work? Maybe I have trouble feeling sorry for other people when I’m busy feeling sorry for myself?
Is it just me?