All day, Sirius was contemplating the meaning of life in his own private study. Well, not his private study, as he didn't have one of those, but in his childhood bedroom. But he was contemplating the meaning of life. All of the colors; both happy and sad, both vibrant and dull, both light and dark. The dark, sad, and dull colors flowing throughout his room and all through the house. The bright, light, happy, and vibrant colors of the amazing yellow sun and it's rays intermixing with the brilliant blues of the high noon sky.
He didn't just think about colors, however, and his thoughts drifted over to actual human life. Hundreds and thousands and millions and billions of people socializing on one planet—not that he knew that; his family hated everything muggle so he didn't know these things—but his childish imagination thought of those things. Billions of people living in somewhat harmony; what a wonderful thing!
From there he began to think of how there were billions of people roaming on the earth. How did they get there? How are people created? How do people arrive on Earth to live and mingle and all that?
And then he realized: to begin to understand the meaning of life, you need to understand where and how people come from. So he raced down the stairs to the kitchen where his mother was usually located to ask her.
"Mommy, where did I come from?"
Walburga had to pause for a moment. What could she tell her baby boy? He wasn't old enough like Regulus to know the truth, but he's smart enough to know that the classic 'You were delivered to our door by a stork, all nicely wrapped up like a gift' story was a lie. Besides, little Sirius was certainly not a gift. No, he lost all of his potential long ago, when he started to seem to drift away from the traditional family beliefs, at least of the past 400 years. The only thing he had brought with him was troubles upon troubles, so…
"Sirius, you came from the devil himself." There, that was a harmless little lie. It might not even be one, as he is the little devil child. Plus, he's already truly left the family, and this home. Harmless.
Sirius, however, did not think that this was a harmless little lie. Whether his mother meant it or not, her tones certainly indicated that way. Eleven years of constantly not fitting in, eleven years of daily reminders that you aren't loved, eleven years of being belittled an infinite number of times. This just confirmed it. He wasn't wanted. Never was, never will be.
His head down, he slowly slumped away, completely and utterly dejected. Only one thing remained positive in his world anymore. In two days time, he would be on the Express going to Hogwarts.
When he got to Hogwarts, he had just made fast friends with James Potter, enemy of his biological family, but the cornerstone of his future family. He and his brother both got sorted into the same house, the rival of his old family's Slytherin house, Gryffindor. And his life was forever changed for the better.