I think if we hear something at a very emotional time in our lives, it brings it all back.
Somewhere over the rainbow, played at a dear friend's funeral accompanied by pictures of his life.
Leonard Cohen's Hallelujah. At a conference in Cape Town, the Mayor had organised for a local choir made up of young children from the townships (slums) to stand on stage and sing this to us, we were all in floods of tears.
Make me a Channel of Your Peace - sung at the funerals of both my parents
Oh Holy Night - magic of Christmas, not sure why this one in particular
Ave Verum Corpus - heard this being played whilst walking round Mozart's house in Saltzburg on a magical holiday, it was just beautiful.