First of all, understand that I am not the most enthusiastic TV series viewer. I spent much of my adult life without watching any television and only recently began to watch TV regularly - mostly in response to very dark and very cold Alaskan windows. So, take what I say with that in mind.
I stumbled across NCIS during the 2014 season; intrigued, I bought Season 1 and I enjoyed it. There are two episodes in Season 2 that I have really enjoyed, Doppleganger (the parallel team idea was very entertaining), Chained (giving good play time to DiNozzo), and Witness (show casing McGee). Lt Jane Doe also was well thought out with few dangling plot devices.
But I am finding some things I don't like in Season 2 that are either a product of different writing or something about the game plan I didn't notice before. Tony and Caitlin, especially, come off as stupid, when Gibbs always knows the score, for example. Sasha Alexander's character is frequently reduced to nothing but snide comments on Tony much of the time (no wonder she wanted out of her contract). Then, there are the twist endings that aren't fully explained to my way of thinking. For example, in the episode title, Black Water, a car was pulled from a lake with decomposing skeletons and a bullet hole lodged in the door. The Twist at the end was the bullet hole was exposed to water for less time than the rest of the metal in the car. Question - how did the perpetrator fire the bullet into the side of the car - haul the car out, fire the bullet, then let it roll back into the pond? Did he somehow fire underwater? You see my point.
But, having said that - I still like series. Overall, I find it more entertaining than many and will probably keep buying the seasons right up to the most recent. It is a comfortable way to spend an evening.