When I was doing the screenwriting course, we were constantly being reminded of one of the golden rules of writing: Show, don't tell - describe the scene through actions, rather than words.
And this is why I love The Wire so much. Everything is shown, not told. The writers assume the audience is smart enough to figure out what the characters are doing, without resorting to have the characters ask each other what they are doing.
There's a perfect example of this in Episode 4 of Season One, "Old Cases". This is the entire dialogue (taken from the subtitles on the DVD) between McNulty and Bunk as they dig through an old crime scene. Gold star if you can figure out their actions from their dialogue.
This is the one?
Yup. Hasn't been rented since.
What the fuck?
Oh, the fuck.
Fuckity, fuck, fuck.