Context-aware ubiquitous applications are entering everyday life bringing new services to mobile users. However, their implementation remains challenging as there exist very few models and tools to guide application designers and developers in mastering the complexity of context information. This becomes even more crucial as the context of a user is by nature imperfect since it is collected from sensors with a limited capacity. One way to address this issue is to associate to context information some meta-data representing its quality. We propose a generic and extensible design process for context-aware applications taking into account the quality of context (QoC). We demonstrate its use on a prototype application that we developed for sending flash sale offers to mobile users. A Flash sale notification comes with indications on how to reach the shop where the offer takes place. The level of details of these indications and their form depend on the QoC of the location information. Through this example, we show how the addition of a context-awareness aspect in an application design process leverages the overall quality of mobile and ubiquitous applications.