One where absolutely everything is perfect - the beat, the melody, the arrangement, the structure, the lyrics, the subject, etc.?
That’s a good question. I’m very ‘mood based’ when it comes to music and few songs hit the same at any given time.
But maybe ‘Huldra’ by Gåte.
‘Twenty One’ by The Cranberries is also a contender.
Unwritten - Natasha Bedingfield
It’s a banger and works in any situation. Dance floor? Everyone’s singing and bopping. Alone in your room depressed as fuck? You’re cry-singing your heart out. Wedding? Lovely song about starting a new chapter together. Working out? It’s a motivational masterpiece. It’s so versatile and so good.