If you’ve ever seen a movie in 3-D  “Avatar,” “Up,” “Polar Express” and so on  then you’ve already seen the effect. You wear plastic glasses, and you get a sensation of depth in the movie image. Sometimes the filmmaker pulls cheesy stunts like having a character shove a pole “out of the screen,” nearly into your face; at other times, as in “Avatar,” the 3-D effect lends a subtler depth and realism to a scene.

At C.E.S., the screens were big, the images were high-def, the sound systems were state of the art, and the video samples were vivid and punchy. They made 3-D TV seem fantastic. You almost couldn’t wait to buy one when they come out this summer.

But once the retractable leash pulled your C.E.S. demo glasses back onto their pedestal for the next customer, you’d be forgiven for having a few doubts.

First of all, those glasses. E-w-w-w. Do we really want to have to put on glasses every time we sit down for some TV? Don’t we lose something when we look around the room to exchange glances, and we can’t see anyone’s eyes? Do we really want to nuzzle up to our fiancées and spouses with those things on?

You’ll get one or two pairs of glasses with each set. Additional glasses will cost $75 or more. So if you invite 12 buddies over for a Super Bowl party to inaugurate your expensive new 3-D set, you’ll have to lay out $750 just so everyone can watch the game. Better hope nobody fails to show.

Image Active-shutter 3-D glasses are a far cry from the flimsy spectacles of the past. Credit... Steve Marcus/Reuters

(And no, you can’t ask your friends to bring their own glasses. The TV manufacturers haven’t agreed on a standard, so one company’s glasses may not work with another company’s TV. Argh.)