I don't understand all the questions about CUT?

To me, it was pretty straightforward: the extra is real, none of it is a dream. At the end, the director, traumatized, "switches" his wife and the kid in his mind and strangles his wife, thinking it's the kid. I figure he felt insane guilt that HE didn't have the "strength" to save her. Her fingers were chopped off and she had to commit a horrible act to save herself. The kid saying "I will get revenge" shows that he's going to be just like his father (cycle of violence). The extra brought the director and his wife down to his (the extra's) level of depravity, and the director couldn't deal with it. The kid was wearing a wig because the extra wanted him dead, but said he couldn't bring himself to do it. The only thing I thought was open to interpretation was whether or not the director was actually having an affair or if he was trying to show that he wasn't really a great guy to mollify the extra.

I don't understand all of the confusion - am I missing something? I've seen a few of Park's other movies and they're all grounded in reality, but with heavy symbolism, occasional surreal images and expansive camera angles.

They're coming to get you, Barbara!