Belgians are in general not patriots. Few Belgians know the lyrics to their national anthem (if they recognise it, that is), and you often hear people complaining about how things work in this little country. But still, if there is one thing that unites Belgians, it is that they don't like to be recognised as Dutch. Psychologists and historians could probably come up with scientifically-recognised reasons why this is the case, but like all good scientists, I have my very own opinion about the matter :-)
Most of us know that people in the Netherlands speak dutch (even when they speak english, right? :-). However, several people have asked me where I learned to speak dutch, even though they know I speak flemish. So apparently, not everyone knows that dutch and flemish are in fact the same language. Dutch-speaking people use the same dictionary and the same grammar rules as Flemish-speaking people, for example.
Given this fact, you can imagine my surprise when, as a Belgian in the Netherlands, I find out that some people do not understand what I am saying. This happens a lot in stores, train stations and any other public place. I ask something in what I think is perfectly well understandable dutch, and I see them starting to look puzzled, as if I'm an alien, and then I get an answer in english! Only after mentioning several times that I do speak dutch (in dutch!), they start realising that I must be one of those strange-sounding guys from the south.
The reason I believe this happens is that the difference between the dutch and the flemish dialect lies not only in the pronounciation, as most Belgians I know seem to think. It is of course true that flemish-speaking people immediately recognise a dutch-speaking person, and vice versa, but this is simply due to the different sound. People from the west side of Belgium also sound different than those from the east side, or people from the north side of Holland sound different from those from the south side, but no Belgian I know starts speaking english to a guy from West-Vlaanderen, right? So, my guess is that it has to do with the way the language is used, that is, the expressions that people use. So, as a survival kit for people crossing the border, here is a list of dutch → flemish expressions that I've collected over the years:
Now, dutch people seem to think that their way of using the language is the right way, and that we belgians just speak an odd dialect. This is rather strange, given the fact that it has been proven numerous times that we know the language a lot better!
Granted, I have to acknowledge that these language issues do not only confuse dutch people. When I'm in France, people also think that I speak a strange french dialect, even though the french spoken by Belgians is (again!) the official version. Proof is that, even when I'm in the UK, people think that I speak french, allthough I'm talking in english ...