The fact that this uber-violent, pulpy drama about bikers of all sub-cultures is actually a loose adaptation of one of William Shakespeare's best works is mind-blowing. We've seen several people and publications point that out this season, but it's actually been there right from the beginning.
While not officially confirmed until season 4, the implication that Clay Morrow murdered step-son Jax's father John was clear and present since the pilot. Just sub in John Teller's manuscript, which influences Jax's opinions on the club from the grave, for the ghost of Hamlet's father, and the rest of the parallels fall into place. Although admittedly, Gemma is more of Lady Macbeth than Gertrude.
Obviously the series isn't a point-for-point adaptation, which it shouldn't be. As an honest-to-goodness translation it would've collapsed long ago. But as a loose interpretation, Kurt Sutter's baby has managed to work from material the contemporary masses would probably turn away from and spin five highly rated seasons out of it—not to mention, he's made it work within a biker sub-culture that most wouldn't expect to find Shakespearean undertones. That's no small feat.