Behavioral and neurological findings show that our cultural background influences the way we perceive and interpret information. This also impacts which user interface designs we find most intuitive, appealing and trustworthy, and how we interact with technology in general. In this talk, I will (1) outline how perception and preferences differ between various cultures, (2) describe the implications of these differences for user interface design, and (3) discuss a possible solution to the conventional "one size fits all" approach in user interface design with an approach called 'cultural adaptivity'. The main idea behind it is to develop intelligent user interfaces, which can automatically adapt their look & feel to a user’s culture. Rather than only adapting to one country, cultural adaptivity is able to anticipate different influences on the user’s cultural background, such as previous countries of residence, or differing nationalities of the parents. The presentation concludes with the results of several experiments conducted in Switzerland, Rwanda, and Thailand, which showed that cultural adaptivity improves both user satisfaction and work efficiency.