22. Justine Henin:
Henin was as dominant a woman’s tennis player to ever compete. From 2002 to 2007, she ruled over the sport with peerless efficiency. She spent an alarming 117 weeks ranked as the world No. 1 during that time period, winning seven Grand Slam titles. Henin won four French Opens, two US Opens, and one Australian Open. She ended the 2003, 2006, and 2007 years as the world’s top-ranked player as well.
Heading into the 2008 French Open, however, Henin shockingly announced her retirement from the sport. She was only 26 years old. Nagging injuries were mounting for the tennis superstar, but she simply cited fatigue from 20 years of focusing on tennis alone. Henin later made a comeback in 2010 and ultimately retired a second time for good in 2011.