Bleb – a bubble
Sirius
)O(
For most of his first eleven years, Sirius assumed himself to be a regular Black. He didn't see himself as different from the rest of the family in any significant way, and that was perfectly fine with him.
Then he went to Hogwarts. He got sorted into Gryffindor. Everything changed.
For the first time in his life, he met people who weren't perfect young Pureblood men and women. At first he was wary of them, but quickly came to see that they weren't anything to be wary of.
He must have been living in a bubble, he thought, not to know that people who were not Purebloods could be interesting.