My "UIST vision" is to fundamentally change our approach to designing intelligent interactive systems. Rather than creating parasitic systems, our goal should be to create "human-computer partnerships" that establish symbiotic relationships between artificial intelligence (AI) and human users. This requires assessing the impact of users interacting with intelligent systems over the short, medium and long term. We also need to ensure that users control their level of agency, ranging from delegation to retaining full control. Finally, we need to understand how users and AI systems affect each other's behavior over time. This implies we need to explicitly support "reciprocal co-adaptation" where users both learn from and appropriate (adapt and adapt to) intelligent systems, and those systems in turn both learn from and affect users over time.