‘Doe maar normaal, dan doe je al gek genoeg!’ is probably a quote that would sum up the Dutch mentality. It means that you be normal and don’t get carried away, a literal translation would be ‘Just act normally, then you act crazily enough!’.
Dutch people are direct, we see this being honest. Foreigners however, can misunderstand our directness for bluntness. The Dutch love to complain, especially about the weather. They are also very punctual: when planning a meeting, everyone pulls out their pocket diary (or smart phones nowadays ;)), commitments have to be honored and arriving on time for an appointment is very important.
The Dutch love ‘gezelligheid’, a concept that is difficult to explain in English. According to Wikipedia is one of the most important Dutch words because it describes the ideal cultural setting, one that is cozy and inclusive. The German term Gemütlichkeit (‘gemoedelijkheid’ translated in Dutch), which invokes cosiness and comfort, and has also been adopted by the English language, covers some of the possible meanings of gezellig, but not all.
The Dutch value their privacy, they do not appreciate anyone dropping in unexpectedly. If someone does, however, or if a workman comes to the house to fix something, they always offer coffee.
Upon meeting, people who don’t know each other well shake hands. When friends meet, first women kiss or rather touch cheeks three times: right, left, right. Then men touch cheeks with the ladies the same way: right, left, right.
Ofcourse I could keep writting on an on about Dutch mentalitly, there are so many different aspect that I haven’t even discussed yet. If I did this post would go on for pages and pages. There are some fun books about the Dutch and their mentality, for example The Dutch, I presume? or The Undutchables