I finished season 1 a while ago and I'm halfway through season 2 now. With my new work schedule + classes it's hard to binge watch shows.
Anyways, for season 1, Wilson Fisk is such a well written character. You hate him then they explore his background and you start to feel bad for him when suddenly you smack yourself in the face and say "Wait...why should I feel bad for this asshole?" The multiple ongoing wars in season 1 was really good as well.
Like I said, I'm halfway through season 2 and I really love Frank. Once again another well written character.