We call it "sexual tension" even though it describes a whole lot of things that don't have much to do with each other.
It's what popular TV series of all sorts hope to set up and feed off for as long as possible while viewers keep returning every week to see if it's finally resolved in the sack.
If you've got a "will they or won't they?" question behind everything else that's going on in the foreground, you're probably in TV series clover for quite a while.
Take ABC's terrific American version of the BBC's "Life on Mars" -- particularly Jason O'Mara who is constantly dodging (or not) women right and left even though everyone who watches the show regularly is rooting loudly at home for him to hook up with Gretchen Mol.
Viewers spend every show wanting to tap O'Mara on the shoulder and say: "Excuse me but have you actually LOOKED at that woman? At how gorgeous she is? Have you seen the love pour out of her eyes every time she smiles at you? Even on Mars, they might notice that."
And then, of course, the classic current case on the tube is Bones and Booth, the perennial precoital partnership on "Bones," which Fox has recently relocated to Thursday nights to steal a little thunder from "CSI," now that star William Petersen has taken a flying bye-bye and the show's once-fresh nerdly heart has been removed.
Consumers of tiny tidbits of infotainment drivel have long since picked up on TV Guide's news that, at long last, after fondly but chastely melting in each other's eyes for a few seasons now, Bones and Booth are going to get the deed done.
Or, at least, give onscreen evidence of having done so -- like, say, wake up in the same bed and/or switch back their cell phones after the previous night's confusion (or some such corny thing).
As satisfying as "Bones" watchers are no doubt going to find all this, there are notable perils to TV series consummations.
They always worked on "NYPD Blue," for instance, because the show always had a naturalistic sense of both sexual heat and subsequent relationship frosts (especially of the marital variety).
"Bones" is from a different TV universe altogether, where everything emotional is artificial and soapy and mere seconds away from a wink and a grin and only the bones and tissue on autopsy tables are allowed to pass for real.
Bones (Emily Deschanel) and Booth (David Boreanaz) have scaled the jolly heights of absurdity this season by going undercover in a circus as a Russian knife-throwing act. Booth, it seems, suddenly started displaying the ability to knock the ash off a cigarette with a knife thrown 25 yards away. It was only slightly less ridiculous than it would have been if Gibbs, on "NCIS," suddenly revealed a talent for flying on a trapeze.
But that was the point. Though the show is presumably based on the mystery novels of Kathy Reichs, it is never in any danger of skirting TV realism, much less naturalism.
So when Bones and Booth actually do collide romantically at season's end (so they say) you might as well be watching Donald and Daisy Duck (or Rock Hudson and Doris Day).
Meanwhile, elsewhere on Thursday nights, "Bones" has clearly sapped some of the procedural investigative fun out of "CSI," now that Petersen has departed and taken the show's original identity with him.
Let's all be frank here: a certain pomp almost always seems to attach itself to Petersen's replacement, Laurence Fishburne. They've tried to play against it on the show by making him a tyro in the CSI trade and by using his natural solemnity (his behavioral key of C-major) comically.
But with that leading role substitution, the personality of the show has changed completely.
What was once the impregnable top-fated fortress of Thursday night viewing is now just a viewing habit that may yet prove depressingly easy to break.