No can have a lot of uses and a lot of meanings.
It can also be the result of making stupid referendums.
They are not stupid per se, but for the fact that they ask to vote people who do not understand what they are voting for.
Saying no to an unwanted and unshared Constitution would be a wonderful reason why to say no, the problem is that the majority who voted no probably didn't even read it.
They said or they informed or they convinced...that voting no was undoubtedly the best way to vote.
What in reality that no meant was:
We want a better life, you promised that Europe would bring us just nice things and look what we had:
1) The Euro was the best way in many Nations to fuck once more the consumers.
2) Europe for now instead of meaning a new beginning meant just new taxes
3) Our economy is going worse instead of better
4) It looks like our politicians cannot do much to improve the situation
5) Once and for all, we would like a Europe and being European, but we still are too stupid to understand that having a common language doesn't mean to loose one's individuality, having a common currency doesn't mean that everybody gets immediately richer, having a Union doesn't mean that the rich gets richer and the poor gets richer too.
It means that the rich gets less rich and the poor less poor.
That is why the poor welcomes it and the rich doesn't...