Dealing with expectations is really a tricky issue. If you have excessive expectations without a proper foundation, then that usually leads to problems. On the other hand, without expectation and hope, without aspiration, there can be no progress. Some hope is essential. So finding the proper balance is not easy. One needs to judge each situation on the spot.
The essential nature of mind is pure. It is based on the belief that the underlying basic subtle consciousness is untainted by the nagative emotions. Its nature is pure, a state which is referred to as the mind of clear light. That basic nature of the mind is also called Buddha Nature. So, since the negative emotions are not an intrinsic part of this Buddha Nature, there is a possibility to eliminate them and purify the mind.
His Holiness the Dalai Lama