I love partner dance because it brings a wonderful interplay of steps vs improvisation – an interplay of structure and chaos.
Our steps are what are used to create the structure of the dance. These steps are what constitute a style of partner dance in it's traditional sense, a tango, a waltz or other fundamental steps that the dancing couple both know and understand. Unlike solo dancing, when dancing with a partner there needs to be a structure of that we both understand to make the dance work between us. However, if we dance all structure without a dollop of our own creativity or improvisation we can find that dancing becomes predictable and stagnant. Partner dancing also needs improvisation to give it life and present moment connection between the dancers.
Improvisation is our way of interpreting the music and moving with the flow of how we feel inspired to move in the moment. The creativity expressed to the music playing. But just like structure, if the partner dance is all improvisation without any structure underlying the style of dance, the couple may become so separate so as to not actually be dancing 'together' at all any more.