In my place, my friend next to me was consistently nagging me in the first hour that it's getting boring. Then towards the second hour I saw him shut up, and the last hour I could see him with mouth opened wide.
When the credits started rolling, everyone in the cinema hall sat 5 minutes in silence, trying to recollect and think about the events that happened, and distant claps started to sound loud and louder, till everyone stood up and went out of the theatre. Especially I haven't seen the audience talking so much to each other while they were on their way out.
My girlfriend was crying next to me during a scene, and it was really powerful. There were a number of scenes that was emotional.
If you thought Inception as brainy, Interstellar will make it feel like a Disney movie.