Sirens' Song:

"What was the Siren song?"

“All the things you want it to be. Then, all the things you wish you never wished for.

It was the delicious itch you go to scratch but find it’s under the skin, you can’t reach it. So the delicious itch becomes unbearable.

It told you what you most want…is what you most can’t have.

And what you most can’t have…is what you already had...and lost...

It was the song of all the promises I failed to keep. And it told me I don’t really want to go home.”

I shall not ruin your personal experience, dear reader, on this incredible piece of that magnificent movie (assuming you didn't reflect on this part yet). I will only just add some pinches of salt that might enrich your POV.

Nolan inverted the Sirens' effect that Homer developed. Instead of offering omniscient wisdom in relation the external world, Nolan's Sirens sing a profoundly personal song of a much stronger essence: the voices resonate with the vices of the intended listener. The lyrics of the song offer nothing but the cruel truth that breaks egos and demolishes nostalgia. This way, the song was fine-tuned to the fragile nature of the human experience (particularly to Odysseus'), and it was, arguably, the heaviest psychological test of the Odyssey.