I think, with hindsight, that the music that reduces you to blubbering wrecks fits into two categories: that which you associate with a sad event (funeral of a loved one, for example) and the qualities in the music itself. The examples I gave in the OP have intrinsic Blubbering Wreck ingredients and, for me at least, no outside connotations. "Cwm Rhondda", for example, I have sung many times as a very joyful piece of music. Now I associate it with my mother's funeral and perhaps there are sad connotations there. My family Can Sing Very Well and all the harmonies were there for my mum's send-off, fortissimo, which ultimately was a celebration of 93 years of wholly fulfilling life.