One woman said, "I just got a splitting headache".   An older fellow nearby said "So did I!".  A young child, rubbing his eyes, said, "my eyes hurt".  Another person, throwing his 3-D glasses into a trash can, said "It must be these terrible 3-D glasses!"   Several people then commented that they never wanted to see a 3-D movie again.
 
Of course, the 3-D viewing glasses had nothing to do with it.   Nor the fact that the movie happened to be in stereoscopic 3-D.  It was entirely caused by a preventable error.
 
It is doubtful that the producers or the exhibitors were even aware of the problem.   When they viewed brief dailies, their visual systems compensated for the errors, so that things "looked normal".  After viewing enough material every day, their eye muscles had become acclimated to the unusual stress, so they could view comfortably what people not so used to it would find painful.