I remember reading and love these books growing up! One of the characters that struck me was Nancy's boyfriend, Ned Nickerson, who always behaved like a two-dimensional supporting character. Though he sometimes saves her at the end, he often feels like a minor character, always telling her he's concerned for her safety. I found that funny until I got a bit older and realized that's usually how women are treated in novels where there's a male protagonist (e.g. Bond women are never given much complexity).