Snape, as a young man, was an extremely insecure, vulnerable and painfully embittered person with a colossal inferiority complex. From the year dot, he strived to be part of some greater cause for the sake of recognition, admiration, authority or, if need be, fear. He grew up in complete and utter poverty under a vicious father and a witch mother, leading him to be a very fearful person. This also drew him towards Lily Evans, to whom he developed an increasingly powerful love for - however, though she ambiguously regarded him as a friend, she did not return any romantic affection. Though according to JK Rowling, had Severus not fallen in with the wrong people and the Dark Arts, Lily would have returned his romantic feelings. Snape's prejudice was very debatable, as he was renowned for hating Muggles like Petunia Dursley, but he did not appear to regard Lily in the same light because she was Muggle-Born - this might have been influenced by his love for her. He would turn cold and callous towards what was seen as racially inferior by others if it meant being liked by his peers, shown by him viciously scorning Lily's blood status in front of James Potter simply so that he didn't lose face - an act that he deeply regretted afterwards. Snape was a determined and highly driven man, and quickly developed supreme confidence in his own talents and abilities. He was, in his own right, an extremely powerful wizard, so this assurance was not unjustified. He would also become critical towards the magical powers of others, particularly Hogwarts students he didn't like. However, despite his immense prowess as a sorcerer, Snape relied on his genius-level intelligence and power of mind to survive in a world where magical powers were considered the defining trait of everyone around him. While his antagonism against Harry was due to his trauma of being bullied by James, and then seeing his bully "reform" to build a relationship with Lily, as well as seeing his eyes (his mother's eyes) reminding him that she was dead, another element was his self-loathing for unintentionally pushing Lily away and failing to prevent her death; Snape felt unworthy of affection, especially from his true love's child, thus made an acerbic habit to make Harry dislike him. Similarly, Snape demanded that Dumbledore keep his love for Lily secret, either out of feeling undeserving of association to her or pragmatism to make his infiltration into Voldemort's restored Death Eaters more believable, or a combination of both. Snape was, finally an enormously brave man - throughout the course of the series, Snape placed himself in unimaginable danger every day of his life, in his efforts to protect Harry from any harm that came his way - he even protected Harry from a werewolf by covering his body over Harry, risking extreme physical harm to his person. Snape outwardly seemed cold-hearted to most, but he was in reality a person who possessed a deep capacity for love. Everything that he did in the latter part of his life was motivated by his devotion to Lily Evans, whom he loved very deeply. He was one of Dumbledore's most reliable allies and in his role as a double agent, took great personal risk in ensuring Harry's safety at the hands of Lord Voldemort. Snape willingly sacrificed his reputation and life to be seen and condemned as the traitorous murderer of Dumbledore, all in the intent to ensure Harry's safety and the Dark Lord's destruction. "Always."