He was so angry because the invited took his message very lightly,and got busy doing their own things,totally disregarding their host.he was also angry because he had spent his time,money-Given them the best of what he possessed,yet they ignored his invitation,when it cost them very little or nothing as everything had been paid for.

Jesus was telling the Jews,His own people,to whom he had been sent ,that since they took him for granted,and assumed the fact that they were the people of God,then the invitation to sonship had been extended to the rest of the world,by the gracious and generous God.He is also informing  those who reject him that destruction is their lot,and that they can not just come in,unless they acknowledge Him,get to wear his germent(bridal clothes as the condition for sonship.