The reason Horatio is so much more of a loose cannon than any other head of the lab on the other CSI's is......because Megan was written out early on and since then he's had no one who is equal enough to pull him back to reality. Every other CSI supervisor has an official assistant who provides some measure of grounding, and in the episodes Megan is in we see her do that for Horatio. But no one replaces her in the assistant's role after she quits, and Horatio gets progressively crazier from that point on.
Horatio Caine is suffering from severe Post Traumatic Stress Disorder.Horatio's complete lack of a sense of humor, his extreme determination and ruthlessness with bringing criminals to justice, and his overprotective nature towards the innocent (especially children and families) seems to indicate that the events of his past as a soldier and the loss of his brother affected him a lot deeper than anyone knows. He either cannot or will not come to grips with it and move on.
Horatio Caine has Asperger's Syndrome.This explains his inability to make eye contact and his troubled relationships. He also has odd postures, "stimming" with his sunglasses, and a hyper-focusing trait wherein he is obsessed with certain trivia (bomb squad, anyone?)... True Companions - possibly his only friends. He has incredible detection skills and is master of the Click Hello and snappy one-liners, and is terse in general. He appears to have ninja skills. The split happened because he went to seminary (Walter's casefile mentioned he was doing well in religious studies) instead of the ladies' clothing factory.
Horatio Caine is in a coma or some other dream state, and CSI: Miami is his fantasy world.What other possible explanation is there for the series's lionization of a guy who runs around acting like a major douchebag? The women want him; the kids all love and trust him despite his wrinkled face, unnatural speech, and creepy whispering. He's not a good personnel manager at all, but his entire team still worships him. Nobody he suspects of a crime is ever innocent. He makes a new dramatic mortal enemy every three days. He's basically the King of Miami; he can disbar lawyers within five minutes, murder people in cold blood with no consequences except for the ones that make him even 'more' badass, and hire and fire police detectives who don't even work in his department at will. This also accounts for the complete absence of any real world physics or science and of people who aren't morons. Expect the series to end with Horatio: waking up in a hospital bed, or his kid staring into a snowglobe, or his waking in his room with a beautiful woman in his shower, or with him splattering onto the Arctic snow.
Horatio Caine is none other than Jack ThompsonThink about it: he doesn't like video games, acts like he's Batman, and thinks everyone wants him dead.
Horatio Caine is the Smoke Monster from LOST.Like the Island, CSI-verse Miami is only tangentially related to reality. Horatio and the Smoke Monster both live in hot, tropical environments but choose to dress in black. They are arbiters of justice via death. Caine can get to any crime scene, bad guy's lair, etc. because he can transform himself into the black cloud. They surround themselves with people who, given their emotional and physiological problems, shouldn't be allowed access to scissors, never mind handguns and rifles. Finally, Horatio, being of non-human origins, doesn't have human emotions and can only make odd, unrealistic, unconvincing approximations of them.
Horatio Caine is Dexter of Dexters Laboratory all grown up.And he wants to get revenge on all the people he doesn't like MIT SCIENCE!!!!