I got there in time. The host was very kind and offered drinks and even to eat. The mess hall was in the middle of working space and it was too loud and stressful. They ask me to wait while the interviewer will finish his/her tasks. Waited 15minutes. I was interviewed by 2 people. They asked for my last projects, what challenges I had. I answered. When we talked more technical they asked me for why i think in iOS(or any) we cant use UI from background thread. I replied. They reformulated the question. So i repeated with bit different wording, maybe i can explain it better. The whole subject is speculative. I saw on her/his face that that was wrong and bad to them. So I asked if i am wrong. She/him replied "maybe". Here goes my kindergarten. "Alright", i ask then, "what is the right answer" and she/him almost snapped at me. "Why you make me to repeat my question many times, just say you don't know". So I insisted, "I want to learn". She/him: "i don't wanna tell". After few seconds of silence she/him told me why. Then it was awkward silence again for few secs, everyone stood up and went away. Strong opinionated and impulsive people are often very hard to work with. I will stay away. Sent them mail asking not to call me.