It is difficult to relate to Tisha be'Av these days since there is so little connection to all the suffering that happened so long ago. The reason why we have to afflict ourselves on Tisha be'Av is because of the fact that we ourselves destroyed the Temple, because every year that it isn't built it is as if it has been destroyed anew. We are not mourning what was; it is a day to realize that our failure to build it has destroyed it once again.