If something wrong happens to a devotee, he becomes very enthusiastic: "It must be something good!". And it is completely the opposite for the materialist. If something wrong happens to him, he goes to the Lord and says: “What is wrong with You, my dear Lord?”
This is the way of material life, people are trying to come up with the solutions, but these solutions are worse than the initial problems, which they are supposed to solve. The solution is Krisna consciousness, there is no other solution. If we understand this message, it will give us enthusiasm to preach.
Pious people, when they hear the message of Krisna, feel that this is something really relevant and sweet. When we read "Bhagavad-gita" there is this internal feeling: all this is true! ISKCON is designed in such a way to increase the piety of people. We should try to distribute Srila Prabhupada’s books, and if people are not pious enough to get them and appreciate them, we should give them some prasadam. But we have to understand the importance of these books in our life. If you read "Srimad-Bhagavatam" with proper eagerness, you will see Krisna on every page of this book, and you will reciprocate with Him directly.