The New York City of "Shame" is a place so cold, so distanced, so removed from flesh-and-blood humanity, that it's the only place a man like Brandon can truly be alone.
[Fassbender is] so good as a man completely lost to his baser impulses that it makes "Shame" worth sitting through. Enjoying? That's a relative term. But you'll certainly appreciate it.
The film's numb attitude assumes that Brandon's problem is beyond reach or rescue. So why are we watching, except for high-tone misery and something close to pornography?