Rory McIlroy was enjoying a nice season and was set to defend his two major titles when he suffered a torn ligament in his ankle playing soccer with friends. That became the defining moment of an overall disappointing campaign for McIlroy, and thus led to this perfect answer when asked "what he's learned this year" during his pre-Tour Championship press conference.
"Don't play football in the middle of the season."
Sounds like a plan. And sorry for calling it "soccer," Rors.