I had previously assumed that my nausea during 3D movies was only because of the ones I had seen were roller-coaster types (I couldn't understand why other people weren't nauseous!). But I saw Avatar last night, and from less than half an hour in I was clutching my stomach wondering if I could make it through. Two more hours of queasy. Urg. Did somewhat spoil an otherwise excellent movie.
Of course there were some 'roller-coastery' bits; pteradactyls swooping and the like, but I don't think it was that. My husband suggests that my brain is too smart to be fooled by the 3D technology and is struggling the whole time trying to fight it off. That's me, the smart brain girl.