Lady GaGa "Born This Way" (2011)

Where They Sound The Same: The choruses. Listen to them both back to back and you'll hear why Madonna felt like she got ripped off.

Lady Gaga may be thought of as one of the most unique artists in music right now, but if you ask Madonna, her music isn't all that original. Madonna has been very vocal about her belief that Lady Gaga ripped off "Express Yourself" and flipped it into "Born This Way," and countless fan-made mash-ups have further driven the point home. While Madonna has taken jabs, Gaga has remained quiet about the whole issue, and her dedicated fan base hasn't been swayed by Madge's harsh words.