Obligation
  Is a tricky thing.
    When "want to"
      Turns into "have to,"
        You know you've gone too far.
          The "have to"s
        Keep piling up
      Until all "want to"
    Has disappeared,
  And something that used to matter
No longer does.
Obligation
  Will lead to resentment.
    When you feel like you can’t let go,
      That’s when you know
        You need to.