"So the American Civil War is like dating a hot chick. You two have a ton in common, so it's smooth sailing at first. Whenever you find a difference, you just sweep it under the rug. Soon there are more and more differences popping up, but you keep ignoring them because you like each other so much. But they can't stay hidden forever. One day you find that one big difference, then BAM! Civil War! All those long term causes are suddenly just as important as the short term instigator."
And this is why History Grad Students are the greatest lovers.