3D movie picture looks painfully dark, why so?

I went to see a 3D movie today for the first time, but however, maybe
because most of the scenes in movie were dark too, I didn't at all
like the experience, it was even hard at times to make out what was
going on. The 3D glasses make the picture look too dark and remove
most of the contrast. Yeah I liked at times when the 3D effect was
visible enough, but most of the time it was so dreadful for my eyes.