Ok, what is totally absurd for 90 minutes becomes clear in the end. It's a coherent story, if nothing else. The problem with Stay is that it's just a huge trick that's revealed in the end. I mean, the whole movie is quite unnecessary, and there's no real plot. It's just a story devised to keep you guessing what's happening, and then when you get it, you say "Oh, fine, thanks". There's no real motive underneath, existential, moral, psychological or whatever, a reason-to-be such the one that inspired "Enemy" by Villeneuve, for example. Would I recommend Stay? No.