For the elite few it does, and by its happening sets them apart forever. In most sports it means the winning of an Olympic gold or the shattering of a world record. For a boxer, it means the victory that will be remembered above all others, and which places him in history. Only the very great - Muhammad Ali is the prime example - manage to find perfection more than once.
For most, no matter how wonderful their gift and however much they do achieve, retirement brings a nagging, gnawing sense that if circumstances had been different there could have been more. It is mostly a question of timing. An injury here, a mistake there, and everything is spoiled. Or in the case of Lennox Lewis, it may well be the fights that never happened which will dominate his thoughts whenever the time comes to look back.
He should have fought Riddick Bowe and he should have fought Mike Tyson. Now he should fight Evander Holyfield, whose own destiny was carved when he beat Tyson in November 1996. But will he?
After Lewis's fifth-round stoppage of Shannon Briggs in Atlantic City last weekend, the Home Box Office television supremo, Seth Abraham, could only estimate that Lewis- Holyfield might happen by the end of this year, or early next.
First, Lewis must meet his mandatory challenger for the World Boxing Council belt, a capable Croatian named Zeljko Mavrovic, and Holyfield has signed to fight Henry Akinwande in New York on 6 June.
In spite of what Lewis's manager, Frank Maloney, reports as excellent viewing figures in America, HBO are not exactly consumed with the idea of a Lewis-Mavrovic fight. Mavrovic, who does his fighting in Germany, means nothing in the United States, and for all his increasing reputation, Lewis is a non-American.
HBO, who have one fight left in their deal with Lewis, will talk with his promoter, Panos Eliades, and Maloney this week. Maloney was reluctant to accept the published HBO stance. "They were over the moon with the ratings for the Briggs fight. We'll see what their position is," he said.
Just as Lewis did not particularly want to fight Briggs, he probably sees Mavrovic as an obligation. He is, of course, a professional prize- fighter of the highest rank and will not wish to be sold short. However, it is the meaning which Holyfield will bring to his career and life that attracts him, not the payday.
Against Briggs, his impatience and frustration were horribly evident in his careless defence. He was almost knocked down, shaken up, and even as he took control in rounds three and four he gulped great lungfuls of air. His fifth-round win was proof of his fighting heart, power and skill. But while the spectacle was compulsive, it may also tell his camp what they do not want to hear.
It is a possibility worth considering that, whether or not the Holyfield fight happens, the emotional and physical peak of the most successful heavyweight Britain has ever produced came when he destroyed Andrew Golota in 95 chilling seconds last October. And unless they can produce the Holyfield fight quickly to rekindle the flame before it fades out, then recognition as one of the greatest heavyweights in history will have eluded him.