Michael Phelps may have 14 gold medals, but he doesn't have to feed himself during a race or fend off competitors kicking him in the head. He also has two legs with which to kick. Such is not the case for open swimmer Natalie du Toit.
It must be frustrating to win six gold medals (eight total) at one Olympics and have people focus on how you didn't win at least one more. So it's no wonder that Michael Phelps isn't publicly broadcasting his goal for Beijing this summer.