Derrick Rose knows all about them. Last Friday, the NBA All-Star player was in town during his Asian tour for sport wear maker Adidas, and shared his story.
Back in 2011, Rose, a starting point guard for the Chicago Bulls, was named the Most Valuable Player in the National Basketball Association. He was just 22 - the youngest player in league history to receive the award.
The world of basketball was at his feet. Then last year, he suffered a serious knee injury in the first playoff game against the Philadelphia 76ers. Rose was out for the rest of the season.
He went through treatment and vigorous rehab, and in January, he was declared fit by his doctors. But Rose, who started attending practice, never played an NBA game.
Instead, he sat on the bench watching his team lose to a LeBron James-inspired Miami Heat in the second round of the playoffs.
Local fans have been praying for Rose's return so he can help the Bulls win the championship for the first time since Michael Jordan's retirement in 1998.
In Hong Kong, Rose announced he is "100 per cent" healthy and is training hard to get ready for the new season. "The focus is on the team," he says. "I hope to fit in with the team and help my teammates get into the right rhythm.
"Coming back from injury, there are concerns. I may be hesitant about my movements, with my acceleration and my steps, but I am reacting pretty well.
"I will improve to a point where if I want to get to a spot, I will get there no matter what."
At the MacPherson Stadium in Mong Kok, Rose played a three-on-three game with some local A1 league players. His fans were eager to see the high-flying guard in top form but were disappointed. Rose shot several three-pointers, but his trademark drives to the hoop were nowhere to be seen. He just did not seem to be his old self.
In 2010, Rose challenged local singer Chau Pak-ho to a one-on-one face-off. Videos of Rose blowing by Chau and dunking were soon posted on the internet.
At the MacPherson Stadium last Friday, Rose and Chau had another one-on-one showdown - this time in table tennis. Rose played well, so hopefully that success will translate to basketball when he returns for the Bulls' opening game against Miami on October 29.