The danger of the idea posted here is that (i) it sounds very logical and authentic and (ii) it's sort of true. The idea that "If you really deeply care about something, you will do it" is such a simplification that it borders on misleading.

A typical example is literature. Check out Bukowski's "air and light and time and space" (http://hellopoetry.com/poem/air-and-light-and-time-and-space...): I've always loved this poem for explaining succinctly (and artfully) the problem with general procrastination and excuse making:

  ...

  you're going to create with part of your mind and your
  body blown
  away,
  you're going to create blind
  crippled
  demented,
  you're going to create with a cat crawling up your
  back while
  the whole city trembles in earthquakes, bombardment,
  flood and fire.
  baby, air and light and time and space
  have nothing to do with it
  and don't create anything
  except maybe a longer life to find
  new excuses
  for.

This definitely has the ring of truth. But in reality neither novelists and ports work this way. Many writers concede that an important part of the trade is teaching yourself the discipline to write N pages a day (google "writer discipline", you'll be amazed, these guys work harder than coders!)

So let me rephrase: Choosing what to do, e.g. coding instead of being a marine biologist is an act of love; consistently doing good work requires discipline, whether you love your profession or not.