Although I am not an interior designer, I think intrinsically we are all affected in some way by interiors within a building. Interior spaces can strongly dictate the ambience they create, and support what indoor activity or lifestyle people wish to be exposed to or be enveloped by.
It does not matter if the interior is finished with intricately panelled walls, ornate fixtures, classy fittings, sombre dark bar lounge furniture, or a bare, minimalist, open, hard-edged, white-painted, glass-fronted space, or even busy colourful graffitied walls. What is important is that an interior space is emotive in some way. Whether one feels happy within it, or if it inspires or creates a thoughtful or disquieting mood that challenges you.
How functional, accessible and efficiently it can be used will also inform your sense of a space, but these are only some of the elements that are important in creating a distinctively new and unique appearance/experience.