My pick is a song that doesn't get the recognition it derserves, in my opinion, mostly because a lot of people aren't aware that it exists: The Show Must Go On by Queen. Specifically the live version where the band was joined by the iconic Elton John and Black Sabbath's Tony Iommi at the 1992 tribute concert following the passing of Freddie Mercury.
https://www.youtube.com/embed/MqesIQa_4xw?feature=oembedWhen Brian May and Freddie Mercury sat down to write this song, it was about Mercury's struggle with the illness that ultimately caused his death, and his desire to perform despite knowing the end was near. That emotion came through in the studio recording, and it is head and shoulders my favorite Queen song.
Elton John instilled his own emotions into this performance and the meaning shifted somewhat. This version of the song is less about pushing on through adversity to give all that you have within you, it's a bout carrying on despite the loss that you've suffered. And from John and Iommi guesting on the performance, to Brian May and the surviving members of Queen, to every person in the crowd, everyone could feel that emotion.
According to Rolling Stone, "Queen's Brian May recalls that Mercury could hardly walk when the band recorded "The Show Must Go On" in 1990. "I said, 'Fred, I don't know if this is going to be possible to sing,' " May says. "And he went, 'I'll fucking do it, darling' — vodka down — and went in and killed it, completely lacerated that vocal." " You can watch the video and decide for yourself, but I think Elton John absolutely lived up to that example.