Magnetic Hero: By the season 2 premiere all the original members of Five-0 have clearly indicated their first loyalty is to McGarrett. Even Kamekona is willing to enact a Bolivian Army Ending if Steve gives him the word.
Trauma Conga Line: Pretty much his life from the first episode on. His father is murdered while he's on the phone with him, he learns 20 years later that his mother was also murdered, discovers the real reason his father sent him away after his mother died, he's betrayed by a former member of his SEAL team who shoots up his house and tries to kill him, his sister is kidnapped over his continuing of his father's investigation, he's framed for murder by his boss, then discovers that she was Evil All Along and only started 5-0 to keep him occupied, then he gets framed for her murder and sent to prison where he gets shivved by the guy who killed his father, and most recently he was betrayed by a former 5-0 teammate and turned over to Wo Fat who had him beaten and tortured for information he doesn't have. It's been a rough year and half for Steve McGarrett.
Formerly of the Newark, New Jersey Police Department, he transferred to Honolulu PD after his ex-wife Rachel took their daughter there. He insists that he hates Hawaii and only tolerates it because it's where his daughter is.
Hollywood Atheist: Discussed in "Ka Iwi Kapu" to the disbelief of Steve. Doesn't really believe in any higher being or spirits, let alone ancient Hawaiian beliefs. Or at least until the end of the episode
Took a Level in Badass: Danny's competency as a cop is often overshadowed by Steve's extreme amounts of badassery, Chin's disgrace arc, and Kono's Fanservice and Badass. But in "He Kane Hewa'Ole", he is the first one who correctly deduces the culprit's plot. Lampshaded by Steve, who asks, "When did you get smart?"
Kick Chick: She's usually seen using all sorts of kicking techniques when taking down perps.
It Gets Easier: Glossed over. Kono is introduced as a green cadet, fresh out of the academy, but almost instantly is killing bad guys with the veterans (including one with a decidedly non-regulation neck snap in episode five). Compare with Rookie Blue in which a big deal is made of a young officer's first kill. (Of course there is also the slightly disturbing possibility that she's already had experience in this sort of thing...)
Ms. Fanservice: Especially in early episodes. Her role as this has toned down somewhat since Katherine joined the cast.
Ambiguous Disorder: Introduced by the governor with the line "They say he's a savant" and had to fire his piano tuner because he liked to chat and Max found it "emotionally draining". In his off time he investigates cold cases and makes pickles, but doesn't trust phones or watch the news because it's scary.
Rich Bitch: Averted. In early episodes where she is The Unseen her off screen actions and Danny's descriptions lead the viewer to believe she is this, but when she's revealed she is quite reasonable and pleasant once she realizes Danny isn't jerking her around. Danny claims she left him because he wasn't wealthy enough, but she indicates to Steve that it had more to do with not being able to handle the stress of having a husband whose job puts him in constant danger.