The word for today, my friends, is hubris.
Hubris is excessive pride or insolence.
Often, it is referred to as pride before the fall because it is a classic character flaw in heroes.
Basically, the hero has so much self-confidence that he is blinded into doing something exceedingly dumb that proves to be the beginning of his undoing.
One of the interesting things about hubris is that it is so blatant, so obvious that everyone can recognize it (except for the hero himself) and most everyone can guess what is going to happen because of it.
Let's take a hypothetical example... the heroine of a story is feeling so good, so happy, so elated that she declares before a gathering of her friends that she is unafraid of Fate; she boasts that no matter what, she will be going on vacation to Alaska in eight months.
Therefore, no one would be the least bit surprised when one week later a text message arrives -while she is hypothetically grocery shopping and trying to decide what kind of yogurt to buy- with the news that the trip might have to be cancelled; no one, that is, except our hapless heroine who honestly can't frickin' believe it. Despite having studied Aristotle's Poetics on more than one occasion and having written numerous papers on hubris, she is indeed clueless and doesn't see the other shoe inevitably falling.
Of course, Fate has risen to the call-out and tossed a good, legitimate wrench into the works.
ps - hey Fate, sorry about that; you win