Lighting, temperature, humidity, sound and smell. Ambiance. Mood. Vibe. Feel. Every space, every place has its own unique character and dynamic, the sum total of the sensory input of being there. To me the best nightclubs always have more than one room, so that you can leave without leaving, and come back without having left. At Altitude on Russell St here in Melbourne it was the balcony. At the Rhino in Calgary it was upstairs, or if you were upstairs, it was downstairs. At Seven in Calgary it was the patio. Places like Fabric in London and The Guv in Toronto (RIP) are entire ecosystems of diverse space and intensity, and even Calgary microclub Habitat has its own equally intimate side room with its own feel and dynamic.
The place I live now also has its own separate spaces. The balcony is just a few steps away from the DJ booth, but it is a different space and feel entirely. And when the weather and neighbourhood cooperate, it really does provide us with an amazing bit of atmosphere.