Beat me to it HarriGirl!!
Of all the songs, the one one that rings out truest of all (and I feel guilty for offending all those other songs that I adore), then there is only one... 'In My Life'.
Simple.
So much humanity in the meaning. It applies to EVERYONE who has ever (and will have) lived in some way (or ways), or other: Old loves, old friends, old places, etc.... the purest and deepest reminiscenses.
Cheers,
Steve.