We had fed the heart on fantasies, The heart’s grown brutal from the fare.

—William Butler Yeats, “Meditations in Time of Civil War”

I’ve watched every episode of all four seasons of Dexter, but I’ve yet to tire of the opening title sequence, which won an Emmy in 2007. Like the excellent title sequence of HBO’s Deadwood, it’s all about the beauty lurking within the disgusting, the horror coiled among the commonplace. (You can refresh yourself on it online; just search “Dexter: Morning Routine” on YouTube. Check out Deadwood’s opening sequence while you’re at it.)

The camera opens with a macro close-up of a mosquito, preparing to stab its proboscis into human skin. Dexter comes into focus—we see the mosquito is on his arm—and preemptively swats the bug. Self-defense. Thus, the very first thing viewers see is a “just murder.” Already, in the first instants of the opening credits, we are behind Dexter’s eyes, absorbed in his perspective.

What a perfect victim for drawing us to Dexter’s side. Show me a person who doesn’t take some pleasure in killing mosquitoes and I’ll show you someone who hasn’t spent much time in the tropics. I’m not much of an avenger myself, but I’ve passed many steamy nights in cheap guesthouse rooms from Bangkok to Belize stalking the little bastards, finding a kind of grim joy in every fresh bloodstain I left on those damp walls. Unlike most insects, whose offense is just a by-product of them going about their business, mosquitoes  …