How we cite our quotes:
PROMETHEUS. O bright Sky, and you swift-flying winds, and river-springs, and you countless twinkling waves of the sea, and Earth mother of all, behold what I, a god, am suffering at the hands of the Gods! (88-100)
These are the first words that Prometheus speaks in the play, and he doesn't pipe up until well after his captors are gone. Is it a coincidence that he waits until Hephaestus, Power, and Violence are gone before complaining about his sufferings? Or do you think he kept his mouth shut while they were around out of pride—so that they wouldn't be able to see how much they were hurting him?
PROMETHEUS. Would that he had cast me below the earth, below Hades who welcomes the dead, into boundless Tartarus, and cruelly fixed me there with unbreakable chains, so that no god nor any other being could gloat over these afflictions! As it is, I wretchedly endure the buffeting of the winds high up, to my enemies' delight. (152-159)
Prometheus may be enduring unimaginable suffering, but at least he's still got his pride. The fact that he's exposed in a position where even a few people—the daughter of Oceanus—can see him, makes his punishment that much worse. Instead, he would rather be hidden away in the depths of the earth, where no one can see him. By the end of the play, he gets his wish. Do you think he's happy about that?
CHORUS. You are audacious and unyielding in the face of these bitter pains, and you speak too freely. (178-185)
Here, the Chorus criticizes Prometheus for not keeping his mouth shut, since he's just going to make things worse for himself. And he does. Eventually, Zeus gets so ticked off that he plunges Prometheus into a black pit in the depths of the earth—there to remain for centuries, until he's finally hauled up again, only to have his liver mauled by a vulture. Ouch. So why does Prometheus keep running his mouth? Pride.