Justine Henin

If Justine Henin isn't high on your GOAT list, are you even watching tennis? With a backhand slice sharper than your grandma's tongue at Thanksgiving, Henin turned the court into her own personal drama stage. And oh, the Henin fans – ever tried arguing with them? It's like convincing a cat to take a bath. Seriously, her cult following could start their own country. Henin’s game isn't just tennis; it's a masterclass in 'How to make your opponent wish they took up badminton instead.'