Who She Dissed: Lady Gaga
How She Dissed Her: During her MDNA Tour last year, Madonna often mashed up Gaga's 2011 hit, "Born This Way," with her own 1989 hit, "Express Yourself," before chanting, "She's not me," over and over (and over!) again and getting the crowd to chant along with her. It was enough to get the innanets buzzing and force Gaga to issue a response during one of her own shows. "I don't even want to fight back," she said, "because it's more important to me to keep writing music." Madonna 1, Gaga 0.