There are three major obstacles we must overcome in order to be able to appreciate the manifold kindnesses Hashem has bestowed and continues to bestow on us:
We have been enjoying these benefits from our childhood and we are so accustomed to them so that it is difficult for us to begin feeling grateful for them.
People constantly want more than what they have and thus are dissatisfied with what they now possess.
There is some suffering in life for each person, thereby causing the constant and countless benefits of life to be overlooked. In order to become aware of the benefits Hashem is constantly conferring upon us, we must reexamine and reappraise all things.
By attempting to view all things as if we are seeing them for the first time, we will be able to feel their value and recognize the benefits they bestow. We will also be able to discover that even the apparent sufferings are all blessings in disguise.