If your pâte feuilletée does not produce satisfactory results, the following may pinpoint the reason:
The flour was too weak and inhibited the development of the gluten and the structure of the dough.
The fat was too soft and prevented the proper formation of the layered structure.
The fat was too hard and broke through the layers.
The dough was not given enough turns, leaving large areas of fat that could not be absorbed by the dough layers. As a result, the fat ran out of the dough when baked, leaving it undeveloped.
The oven temperature was too low, preventing sufficient steam from developing to promote proper rising.