You are the best in the world by a huge margin. You haven't been beaten for six years, and you're the red-hot favourite for Olympic gold. And then you give it all up, not because injury, or age, or scandal, but simply because you don't find it fun any more.
There aren't many world-class athletes you can imagine doing that. Then again, Carolina Kluft isn't your average athlete. When she walked away from heptathlon, a few months before the Beijing Olympics, the philosophical won a rare victory over the physical.
"I cannot be what I am not," she says simply. "I was not enjoying it, and I have to feel it, to be myself.
"I cannot just go with the flow of everyone else around me. Then I would lose myself, and that's my biggest fear."
Kluft, at the peak of her powers, abandoned the event she had dominated for most of the decade, and took up another - the long jump - in which she stood almost no chance of winning a medal.
To the rest of the world it was a staggering decision. The Swede had won nine consecutive gold medals in major championships. Why throw away sporting immortality for a place among the also-rans? If you do have to quit, why not hang on a few months and go with another garland round your neck?
"If it's no longer fun, I cannot train the way I want to, and I cannot succeed the way I want to," she tells me.
"For me it wasn't 'stick with it and I will win'. I will probably lose, because I wasn't satisfied. I know what I am like, and I don't want to end up doing things because of other people are expecting me to do that. I don't want to lose myself in that way."
We are talking as she prepares for a new chapter in her life. Ten months after a ruptured hamstring almost ended her career, Kluft returns to competition in Daegu on Wednesday.
She does so as a long jumper. Even if the season goes well, she is unlikely to add to her long list of honours. It doesn't bother her in the slightest.
"For me, medals have never been the main motivation. I train all year round and do every practice because I am competitive and I enjoy it, not because of a medal."
But sportspeople obsess about Olympic gold. They will make incredible sacrifices to get one, push themselves through brutal training sessions, endure all sorts of pain and privation just to give themselves a shot. How Kluft could just turn her back on one?
"I already had an Olympic gold. I will never ever think that it's bad I don't have two. It's good enough to have one, in my world.
"I can understand that people think that it's weird, because that's the way it is in this world, but you should do things the best way for you. I live once, and I want to do my career the way I want to do it."
While the heptathlon went on without her in Beijing, Kluft was failing to get through qualifying in the triple jump and struggling to make the final cut in the long jump. Her best effort was over half a metre down on eventual winner Maurren Maggi.
Denise Lewis, her predecessor as Olympic heptathlon gold medallist, has professed herself baffled. "There's only one athlete who has been double Olympic champion in the heptathlon - Jackie Joyner-Kersee. But if there's one athlete I believe could have done it too - in her sleep - it would be Carolina."
Kluft smiles. "I followed it on TV. I missed my friends in the event, of course, and I missed the atmosphere, but that's the only thing I miss. Oh - and the hurdles sometimes. But I didn't miss the competition.
"I was kind of relieved that I wasn't there. I wasn't thinking, what am I doing, I was thinking, ah, I made the right decision.
"I was still happy. I don't think it's a fail to be ninth in the Olympic Games in your first time as a long jumper. It's so different, and it's hard. Sometimes it scares me. But that's what I like - to challenge me. I did my best and I came ninth, and a lot of girls were better than me."
Kluft's popularity has always been as much about her extrovert, animated antics during competitions as her stellar deeds. This is an athlete who took up multi-events in the first place simply because she loved athletics so much - the more events she could do, the more fun - and who can even find pleasure in rehab ("It was kind of cool - I had loads of new exercises to do").
Ninety-nine point nine percent of sportspeople would find it impossible to do what she has done. It would contradict their innate sense of competitiveness, do too much damage to ego and bank balance. For Kluft, there was no other option.
"When you've been at the top for a long time, and you've been training hard, been under a lot of pressure, you get very tired. You need something new. I had a way out with a new event.
"It's been inspirational for me to have this break. Mentally I could reload. Before I would always feel so tired, but today I actually feel I'm getting younger.
"I'm very, very happy every day because I can train every day. My body feels young again. In life I can still see good things."
Kluft is still only 27. Her long jump personal best is 6.97m, just 13 cm short of the distance Brittney Reese jumped to win world gold in Berlin last summer. Maggi won gold in Beijing with 7.04m. From that perspective, she could yet prove the world wrong and end up with another Olympic gold; London 2012 is still in her sights.
Problem is, that PB is four years old. By her own admission she doesn't expect to get close to it this year, not after that hamstring injury. Those last few centimetres won't come easily.
"I'm dreaming of jumping seven metres before I end my career, but I don't want to worry about expectations - I just want to enjoy it. If I go back nine months to my injury, that I can be here thinking about competing just makes me so happy." She pauses. "But of course, I never set any limits."
Even now, heptathlon still exerts a subtle influence. "I will always be a multi-eventer in my heart, meaning I want to try lots of different things. I won't be a coach, or a commentator, or anything like that. I would like to study - I'm very interested in international politics, so I'd like to learn more about global relations. I work for the Swedish federation of the UN, so I'd like to educate myself more with them."
Elsewhere, things have moved on. Wherever Kluft competed before, there was always one familiar figure by her side - a stuffed toy mascot named Eeyore, there to remind her that life was supposed to be fun. But just as she has evolved, so might her companion.
"I'm not going to be that girl any more. As a long jumper, maybe I have to change. We'll see if Eeyore will be part of that. Right now I'm working on being myself, and putting all the energy and joy that I had two years ago into this new, older woman."
She laughs. "Maybe I will take one more toy with me. Him from the past, and something new from the present time. I have new things I know about myself that aren't going to go away."
