We are a really powerless in a world that we cannot control. Oedipus, despite having good intentions, stumbles and bumbles his way into a mess of incredible proportions. His work, his family, and his future are obliterated by his own actions, actions for which he could not possibly have foreseen the consequences.
When Oedipus vows to banish Laius' killer, he is unknowingly banishing himself. When he finally realizes this, he accepts his own punishment without complaint, although he does express his unhappiness. He accepts the consequences that he couldn't avoid. How often do we do that sort of thing in real life?