The classic one is just tearing up your life from time to time; change jobs, move cities, don't talk to old friends, tear everything up and rebuild. The fantasy is that you can start over without all the baggage of how people know you and the history you've laid down, you can build up a new you the way you want to be now. It never seems to work out.
I love the Lance Armstrong myth, even though it has only a small basis in reality. The myth is that before cancer, Lance was a very mediocre cyclist. The disease and chemo destroyed his body, wasted his muscles, made him emaciated, and turned him into a blank slate. Then when he got into recovery he resolved to become a great cyclist, and went into training hard. Any normal human who becomes a cyclist has all the baggage of muscles that were used for walking and playing catch and all the normal things that you do as a kid growing up, but Lance had shed all that to the disease. Thus as he trained up his musculatural, putting pounds of muscle on week after week by riding the bike, he built up a body that was specifically built for cycling. The myth is that only through the disease tearing him down to nothing could he rebuild the super-human cycling metabolism and physique.
It's not true, but I love it. (almost all of the great sports stories are myths that aren't quite true, that let us turn sport into parables, we constantly make up David vs. Golliath myths in sports, or Agincourt longbowmen vs the French, etc.)
Working on this fucking physical therapy every day that seems to never get me anywhere, I dream of tearing down. I imagine that if I could just wipe the slate and rebuild, I could easily fix everything. I actually think that's true in my case; my biggest problem now is that my neuromuscular system has picked up some very very bad habits over the years. Because of my shoulder injury, my long thoracic nerve developed "guarding" which basically means it doesn't fire the serratus. It's perfectly capable of doing so, and my serratus is plenty strong, but my brain doesn't tell it to. Furthermore, years and years of horrible computer use posture mean that whenever I stop thinking about it I slip into a nasty hunch, and even if my back doesn't hunch, my shoulders try to creep forward and up reflexively anytime I need to do something with my arms. If only I could tear down and rebuild, move out of this body into a bowl of stem cells and start anew.