Interaction in Art

I've been thinking about interaction in art lately. Does Art lie in the constructs for interaction that the artist(s) give(s) the viewer(s) or is it the ensuing interaction itself? There are limits as to how much the interaction(s) can be expected, influenced, manipulated, or contrived by the artist(s); if the Art is in the interaction, are the constructs needed? I think Art lies in mediating between the constructs and the viewer's interaction, which admits both attempted control and absence of control as relevant.

Where does success of artwork come from? When the expectations are met by the ensuing interactions? When the interactions exceed expectations in unexpected ways? When the interactions alter the expectations? Need intention even match outcome? I find the greatest success in my own work is when the kernel of my intention is present and ensuing interaction expands my expectations.