People easily drop out from small setbacks. Firmness of aim automatically brings faith. Without faith, the aim can't be stable.
We have to be honest to ourselves in our spiritual life.
It is always a desire, which pulls the mind out in the world taking various forms. Sometimes the form of desire appears as if very spiritual, but deep inside, there is a desire of name, fame, etc.
The biggest obstacle to Self-realization is the deluded mind. The mind which is colored by our ego, attachment and desire.