Angles, curves and shapes give buildings "personality" and stand out.
Colours give the building life and changes the mood of an otherwise plain environment.
Lights brighten up the building and can make the colours, interior and exterior look better. Drab lighting is otherwise plain. Lights can also have fancy designs to be more unique.
Textures give the surface of the building extra definition. A smooth surface from glass mirrors or marble are different from a rougher surface of painted cement.