Nemesis Did Not Punish Evil. She Punished Excess.
A name that means giving what is due
Nemesis takes her name from the Greek verb nemein, to distribute or apportion. Before she was a goddess she was a piece of accounting: the share that falls to you, and the indignation that rises when someone takes more than their share. Hesiod places her in the Theogony among the children of Night, in the company of Doom, Old Age and Strife, and calls her a grief to mortals. In the Works and Days she is one of the last two powers to leave a corrupted world. She and Aidos, the sense of shame, wrap themselves in white and withdraw to Olympos. The pairing is deliberate. Aidos is the restraint you feel from inside. Nemesis is what arrives when you do not.
Hubris was not simply pride
Modern usage has flattened hubris into arrogance. In Athens it was narrower and worse: a deliberate act of dishonouring another person for the pleasure of it. Aristotle defines it in the Rhetoric as doing or saying things that shame the victim, not for gain and not in revenge, but to enjoy one's own superiority. It was a prosecutable offence, not a character flaw. Against that the Greeks set the two lines carved at Delphi, know yourself and nothing in excess, and behind those stood Nemesis, who did not so much reward the good as correct the disproportionate.
She also came for people who had done nothing wrong. Herodotus writes that after Croesus reckoned himself the most fortunate of all men, a great nemesis from the god took hold of him. Undeserved good fortune was itself an imbalance, and the imbalance was the offence. This is the part that unsettles: her ledger has no column for intention.
The sanctuary at Rhamnous
Her principal cult stood at Rhamnous, on the north-east coast of Attica, a short distance up the shore from the plain of Marathon. A Doric temple was raised there around 430 BCE and never quite finished. Pausanias records the local story that the Persians had shipped a block of Parian marble to Marathon for a victory monument, and that after their defeat the same block became the cult statue of Nemesis. He credits the carving to Pheidias. Other ancient testimony and most modern scholarship give it to his pupil Agorakritos, and the marble story is read as legend rather than record. As legend it is exact. Stone brought to commemorate a certain victory becomes the image of the goddess who corrects certainty.
Rhamnous held a stranger tradition too, preserved in fragments of the lost epic Cypria and repeated by Apollodorus: that Nemesis, not Leda, bore Helen, after fleeing Zeus through a series of animal shapes. Retribution as the mother of the war.
The pool, read correctly
Narcissus is usually told as a fable about vanity. It is a nemesis story. In Ovid, a rejected lover prays that Narcissus may love and never possess what he loves, and Ovid names the power that grants the prayer: Rhamnusia, she of Rhamnous. That is Nemesis, identified by her sanctuary rather than her name. Conon, writing in Greek around the same period, has the spurned Ameinias kill himself on Narcissus' threshold and call for an answer.
The punishment is not disfigurement. It is symmetry. A man who gave nothing back is handed a reflection, which gives nothing back either. That is the whole method. Nemesis does not invent a penalty; she returns the thing you did, at your own scale, until the account is level.
The myth, printed heavy: Nemesis Oversized Tee.