For me, the first song that comes to mind as far as structure, lyrics and overall emotive qualities is In My Life by the Beatles. The older I get and the more people that have come in and out of my life, the more that song means to me. To me, it's perfect.
I ... yes. The piano is unparallelled. EDIT: For No One is a close second. The perfect song tells a story, the more evocative the better. The rest just falls into place.
For No One is perhaps one of the saddest songs there is. Maybe the perfect break up song.
I did a project on that song back in high school. Cool fact, the piano solo part was played by George Martin, who played it slower than it sounds, and then sped it up for the actual track. This is very noticeable at the end of the solo where it sounds very quick and impressively well timed.
For sure. America's 'Ventura Highway' is perfect to me. Silky smooth, great harmonies, and alligator lizards in the air. Have no idea what that means, but like, I get it.