I was reading Wuthering Heights by Emily Bronte and was struck by the fact that Heathcliff is described as being dark skinned and had very dark hair. I thought that it was odd that his "father" should pick him up on his travels (after all, if you feel sorry for one little stray boy, you'd have to feel sorry for them all). So, I asked someone else about it.
They said that they thought Heathcliff was his real son and that he brought him home as if he was from the streets in order to cover up any suspicions. And this made sense. It would give everyone a better reason to keep Cathy and Heathcliff apart because that would make them half brother and sister. It would also explain some of why they are attracted to each other. They must see something of themselves in each other, as they are both very wild and unconventional people (for the time anyway).
I just thought this was particularly interesting. I really like the book and was confused by how he seems completely different. This made me think a bit more about the story, and see beyond the words.