Alone by Edgar Allan Poe
From childhood's hour I have not been
As others were; I have not seen
As others saw; I could not bring
My passions from a common spring.
From the same source I have not taken
My sorrow; I could not awaken
My heart to joy at the same tone;
And all I loved, I loved alone.
Then- in my childhood, in the dawn
Of a most stormy life- was drawn
From every depth of good and ill
The mystery which binds me still:
From the torrent, or the fountain,
From the red cliff of the mountain,
From the sun that round me rolled
In its autumn tint of gold,
From the lightning in the sky
As it passed me flying by,
From the thunder and the storm,
And the cloud that took the form
(When the rest of Heaven was blue)
Of a demon in my view.
I thought this poem was fitting because Snape is a very lonely person. As a small child, he was abused by his father and was completely alone until he met Lily. And even then, he was alone in the sense that he loved her and she didn't seem to love him back (although I believe she did). His passion for Potions and the Dark Arts set him apart from the others, and the latter eventually caused his seperation from Lily. In his teacher years, he spends most of his time in solitude--and as much as it seems that he prefers it that way, I think that, deep down, he'd like a friend.
The 'lightning in the sky' could be interpreted as Harry Potter, who he protects despite his hate for the boy, and the demon in his view would be the darkness inside him that he struggled to escape--but in its entirety, it's impossible to escape because of the Dark Mark branded onto his arm,