I really liked how the continuous real-time take gave so many interesting constraints. Everything has to take a perfect amount of time as we can't just fast forward from one scene to another. If you drive, the destination can't be on the other side of town. The elevator should not take forever to reach the top floor. If you wash your face, there's no putting make up on.
Also, all the little details and realizations: "Oh. She's not going to stay and open the café because the movie is not long enough for it to ever become 7 am."
