This is one of he greatest songs of all the time.
But its metaphoric lyrics usually confuse the listeners and the song was target of many parodies and jokes thru the decades.

What's your opinion about it, and do you understand the beauty and pureness of this song?

I always thought the cake was a metaphor for the relationship ending. He's basically reminiscing throughout the song and then in the bridge he tries to be hopeful but realizes he'll always regret losing her.

Levi Stubbs (Four Tops) sings this song best. His version is breathtaking.

It can be considered a metaphor for both (Love and relationship).
But in this case, it's actually a relationship that he for so long dedicated himself for and he saw fading away like a cake in the rain.

I think this is one of the most beautiful songs ever.