On a serious note, I'm surprised nobody's mentioned songs either played at the funeral of a loved one or the dreaded "our song" of an ex-gf/bf/wife/hubby/partner.
For me, I find it hard to listen to Edith Piaf's
.. Rien as it was the last song played at the funeral of a friend's daughter who committed suicide following a severe bout of schizophrenia a few years ago.
I'd known her all her life and she was only 20, fluent in French, studying it at the university where I was working at the time.
I thought I'd cried myself out at the actual funeral and was composing myself to leave when the ceremony came to a close, the curtains closing around her coffin .. then Piaf's voice started up and I began bawling again .. sheesh, I'm not far off it now either
But that's personal.
On purely musical terms, I've not really experienced anything like that level of sadness despite loving both Adagio and that Mahler symphony - both great shouts, btw.
Some boffin on here will no doubt explain how the descending cadences of a recidivist chord regression triggers a certain part of the brain before long though ..