Madonna has several imo and I'm sure a case can made for them all but I'll say American Life.
- a big **** you to the US with the video
- not catchy or radio friendly at all
- the political lyrics
- the lyrics have also been compared to something an angsty teenager would write for their English class
Do It Like a Dude. She didn't just start an era. She launched her career with that song. It's risky, dirty, and a straight up feminist song. Nobody else could've pulled it off, only the Queen of Pop herself.
A song that unapologetically championed the rights that LGBTQ+ people needed in a time where DOMA and bans on same-sex marriage were rampant. The historic 1,000th Hot 100 #1 that was the first to include the word "transgender."
Britney: I'm A Slave 4 U
Gaga: Born This Way
Adele: Someone Like You? I mean it's really weird to see a ballad smashing as hard as it did
Rihanna: Russian Roulette
Katy: I Kissed A Girl