Companies increasingly involve consumers in product design and development, e.g. through built-to-order and mass customization or by integrating data generated at the point of sale into product development and production processes. The latter approach requires that companies provide online tools and interfaces like product configurators for consumer participation in value co-creation. Our research addresses the question how to design such tools to i) ob-tain reliable data and ii) keep customers happy with both products and value co-creation processes. In a lab experiment, we show how two interface elements, default values and task difficulty, affect consumers' product satisfaction, and satisfaction with the configuration process. Results indicate that product satis-faction is influenced by default values while process satisfaction is not, and task difficulty influences neither.