Ten years ago, I was living with two flatmates in a big Parisian flat. Once or twice a year, we organised a party, which gathered up to 90 people, a number we were rather proud of. During those parties, there was a consistent, yet slightly annoying pattern for us as organisers: the best discussions were bound to take place in the kitchen, rarely in our big living room, where we were concentrating our efforts to entertain the party with food, drinks, and music. You see, the kitchen was the room where smoking was allowed. Its door had to stay closed...