Pretty Dark cartoon that's can also be geared towards teens and adults.
For a Nickelodeon kid show,
Hey Arnold really touched on some realistic, serious, and dark issues that even adults and adolescence face. I've never seen a show like this and that's what makes it great.
1) Helgas dark background story of child neglect
2) Oskar and Susie's "effed" up marriage.
3) Helgas extreme (and sophisticated) love life.
4) love triangles
5) bullying
6) clicks ( geeks vs cool kids)
7) preteen scream ( similar to teen today with boy bands and whatnot)
8) parental and marriage projects (egg story! Which is usually a project that high schoolers do with disposable baby dolls) .