Why does Horatio in CSI: Miami always look down while talking?

Why does Horatio in CSI: Miami always look down while talking?

Either he thinks it's cool, he has some sort of problem, or he's looking for money on the ground. I choose option C.

because(sunglasses off) he is making a statement(sunglasses on)..

It's the actor. He did the same thing while on NYPD blue.

because David Caruso must think that doing that makes him seem to be a better actor, just like he thinks that the taking on and off glasses ensures a good dramatic... something or other. He's just a movie reject trying to be so much better than hew is. It's pathetic, and the reason why I dropped watching the show.

He is making a statement