[Kierkegaard] proposed that each individual—not society or religion—is solely responsible for giving meaning to life and living it passionately and sincerely ("authentically").
My philosophy, in essence, is the concept of man as a heroic being, with his own happiness as the moral purpose of his life, with productive achievement as his noblest activity, and reason as his only absolute.
— Ayn Rand, Atlas Shrugged
As a layman who took an entry-level ethics course a few years ago, it would seem to me that both of these theories advocate pursuing that which an individual subjectively values, and to do so without the consideration of others (unless the consideration of others happens to be valuable to you selfishly).
What are the nuances that I am missing?