1. BIlly's mother left when he was two years old. His father, in an attempt to spare his feelings, told him that she had died.
2. This made things rather awkward when she showed up looking for him on his eighth birthday.
3. He never actually found out that she'd run off with a superhero. Which is ironic, as it would certainly explain a lot of things.
4. His father worked in construction, and was often gone for long hours. While generally a well-meaning, caring man, he had a hard time connecting with his sensitive, geeky son. Consequently, Billy spent a lot of his childhood at the library or being looked in on by a neighbor.
5. His goggles originally belonged to his father.
6. Considered gifted academically, Billy skipped two grades in school. The age difference, along with his shyness, made it difficult for him to make friends. (The kids who didn't actively tease him tended to ignore him.)
7. He genuinely used to believe in the goodness of humanity. While he's always believed that where there are positions of power there will always be people who want to abuse them, it was only over time that he came to consider them the rule rather than the exception.