A "sentimental piano-ballad" with a hypnotic, drum-machine-led rhythm that induces a "bittersweet" feeling.

Focuses on the joy of "having fallen in love" with someone and asking, "So why did it end?".

An "open letter to a closed mind" that reflects on neglect and how time erodes memories.

Released from the album ...But Seriously , this is a poignant ballad that captures the "emotional turmoil of a failing relationship". It leans heavily on nostalgia, but with a sharper edge of regret.

Reached #4 on the Billboard Hot 100 in the US.