His stuck moment: As a practicing member of the Nation of Islam, Ali was against the war in Vietnam when he received a draft notice in 1967. Refusal to serve meant a five-year prison sentence, $100,000 fine, losing his heavyweight championship title, and suspension from boxing.
He gut-checks his belief: He showed up for his scheduled Army induction but refused to step forward when his name was called. After the fourth unanswered call, he was arrested.
Unstuck result: Four years after his arrest and conviction, the Supreme Court reversed the ruling. In 1974, he regained his title by defeating reigning champion George Foreman.
(All information comes from public sources and does not imply endorsement of Unstuck.)