Based on a book, 'The Room' by Swedish author Jonas Karlsson, a dark comedy.
I never found it boring in the least. It depends on your preconceptions going into it I guess? You experience it almost entirely in the head of the protagonist, and his internal monologue. The lead plays this to perfection, though I found myself envisioning Steve Carrell in the role! Its certainly not a thriller, in fact, like (I guess) a typical corporate office environment, its mundane, stifling, repetitive.
So why did I like it? It has you guessing, does the room exist? It has you thinking, why is this man like this? Have I known someone like this, and how did I, and others treat them?
The acting and direction are excellent, you buy into all of the characters as ordinary everyday types. The cinematography and soundtrack are faultless, there is nothing to distract you from the monologue. Its 1 hour 41 minutes occupying the head of a troubled individual, who's increasingly fractious interactions with his fellow workers provides drama and interest enough to keep it interesting.