Due to fear, sloth, inaction or lack of ability/intelligence/agency
  1. Do a handstand and go up and down stairs
  2. Deeply understand investing in the stock market
  3. Speak fluent French
    And Latin. And Old English.
  4. Play the accordion
  5. Run for political office
  6. Have six-pack abs
  7. Experience weightlessness in Outer Space
  8. Read the manuscripts J. D. Salinger (or rather his son/widow) allegedly has locked in his vault
  9. Walk the Appalachian Trail
    Or some other long, possibly less-crowded trail
  10. Paint a large, public mural
  11. Spend a Winter in Antarctica
  12. Live a stress-free life