Source: Why is mind not purified?
Even though we keep doing Nama Japa, we complain that our mind is filled with negative thoughts and so on. Why so?
As we progress in our Nama Japa, we should not seek anything else. But our worldly life is filled with hurdles, small or big, and our mind wishes to come out of these hurdles, and hence we pray for the same.
The Nama Japa that we do is used for this purpose. Hence the true goal of the Japa is never realized.
Thus, if we wish for purity of mind or Krishna Darshan, we should seek only that in the name of Nama and nothing else.