As the title says....which song still haunts you emotionally? And why? A (freely accessible) link might greatly bring your point across.
Mine would be: (Typhoon - "Empiricist") https://www.youtube.com/watch?v=9E328pIZWFM
The lyrics go deep and it just touches me. No otherwise special attachment.
Sia - Breathe Me (mainly because of Six Feet Under)
Honorable mention to Dan Folgelberg - Same Old Lang Syne.