Everyone was excited to hear that they now had enough donations and could start the actual building of the Mishkan. Well, almost everyone… besides for the Nesi’im, the leaders and princes of the 12 tribes.
They were disappointed because they had not yet given their donations. Of course, they had planned to donate, but they had decided to first see what was missing and only afterwards fill in the gaps. That was the plan. But nobody could have guessed how speedily the donations would come in.