The desire to be thin became her white whale. Through diet pills, starvation, vomiting, and obsessive exercise, she was determined to be skinny.
Isaac has not beaten Jamal in a 1-on-1 basketball game in the last 20 tries. Jamal is his White Whale.
Baron excelled at video games as a child, although he was noticeably deficient at Guitar Hero, struggling to even play Medium Level songs. After many miserable bouts with failure, he conceded that Guitar Hero was his White Whale, the one game which he could not overcome.
the term derives from the novel "Moby Dick". in the novel Captain Ahab refers to Moby Dick (Who is a white whale) as "The one that got away".
The nice thing about a white whale is that it gives you hope that someday you will be reunited. and ride off happily together into the sunset!