According to our experience, early collaboration with non-expert stakeholders aimed at designing interaction in a user-centered way is mandatory if the goal is a great user experience. We have found that insistence on formal modeling when collaborating with non-experts leads to insufficient results. Therefore, we propose a user-centered approach in order to enable collaboration and communication among expert and non-expert stakeholders. This non-formal approach should be based on a formal model, which also builds the common ground for discussions between all involved project stakeholders.