I love the word hamartia. It sounds like a rule book for bad actors: ham-art-ia.
It's actually a rule for playwrights.
The thing is, every play or story of any kind needs something to kick it into action. Nowadays people tend to think in terms of a MacGuffin. A MacGuffin is something the characters really really want, even though it often isn't all that clear what the MacGuffin is, or why anyone should want it.
In a thriller it's often the SECRET PLANS.
Alfred Hitchcock made MacGuffins famous, but long before him there was a guy called Aristotle who had his own theories about kicking off a story.
What you needed, Aristotle said, was hamartia. Hamartia isn't a thing, like a MacGuffin. It's either a character flaw (the hero is greedy, or jealous), or it's something vital he doesn't know which makes him act (or not act) and thus cause his own downfall.
Something like the fact that his girlfriend's actually his mother. That sort of thing.
(Yes, it sounds a bit unlikely, but in Aristotle's time apparently the gods thoroughly enjoyed jerking people around in that sort of way.)
Word To Use Today: I can't honestly recommend hamartia because it will make you look like a show-off.
MacGuffin is quite cool, though. It was probably made up in about 1935 by Alfred Hitchcock.
Hamartia comes from the Greek word hamartanein, which means missing the mark. There's also a feeling of sinfulness in the word, too.