Current 3D technology results in a dramatic loss of picture quality. In theory they're supposed to compensate for the brightness reduction by cranking up the projector, but I've yet to see a 3D film that wasn't dramatically murkier than the 2D version. You also get terrible judder. And, for people like myself that wear glasses, the fact that no movie theatre distributes polarized glasses designed to fit around a pair of glasses means that I usually have difficulty focusing and get awful eyestrain.

I don't have a problem with the idea of 3D, per se, but its implementation has made watching films in a theatre very frustrating and uncomfortable.