Hmm, I can't say I tend to like side characters *more* than main ones. But I do find myself curious about them sometimes. Like I've requested fic about some of the side characters in the Earth Girl trilogy/series by Janet Edwards, because we see everything through the main char's eyes but there are some really interesting characters that I would like to see more of (Commander Nia Stone, for instance.) A little side note about their backstory and suddenly I want to read the story behind it.

But I'm mostly quite happy with the main ones, lol.