It is well known that giving in to blackmail is a bad idea. It very often leads to higher demands and more blackmail.
This is one of the reasons the Arab Spring isn't going as many would expect. The dictators are usually well aware that their country is ready for some additional freedoms. But they cannot afford to give in too much as it would be seen as weakness and only lead to more protests.
Something similar we see with the "pragmatic" negotiations between Serbia and Kosovo. I was a bit astonished to read the results. What Serbia had conceded was clear but I missed any concrete Albanian concession. It didn't help that some newspaper articles saw Albanian concessions in the fact that they hadn't achieved more.
As I see it the Serbian delegation hadn't done its homework and had not thought up a couple of counterdemands in answer to the predictable Albanian demands. Instead they let themselves be badgered by Cooper who operated with the typical Western arrogance that we often see by Wesern diplomats in the Balkans.
Soon it became clear that my estimate was right. The arrests of Mladic and Hadzic and the concessions at the talks didn't lead to a more benficial view of Serbia. Instead Serbia was seen as a pushover and demands started to stream in. Füle demanded full recognition of Kosovo and Kosovo imposed a ban on the import of Serbian goods.
It looks like Dacic doesn't get this. The primary goal of the EU is to solve the Kosovo problem. But how is of a lesser concern. They will concentrate most of their pressure on that party that seems most likely to give in. At the moment that is Serbia. It looks like the Serbian coalition believes that they can solve all problems and get Serbia into the EU. But you cannot hurry up negotiations. Trying to do so weakens your position and may delay a final solution.
On the other hand I cannot understand the motives of the Kosovo government. The most likely result of the present actions is a reaction from the Serbian government. It may refuse further negotiations or renege the results of the previous negotiations. So Kosovo's boycott will harm its economy and instead of increasing Kosovo's leverage only give it an image of an unreliable partner. The only people who will be benefit from this are Kurti and his ilk.
As a consequence I expect the follow-up negotiations to be much tougher.