One pitfall for those on the path of belief is an inability to understand people on other paths and a temptation to judge them for their doubt or disbelief. Certainty prevents some believers from being compassionate, sympathetic, or even tolerant of others who are not as certain in their faith. Their arrogance turns them into the "frozen chosen," consciously or unconsciously excluding others from their cozy, believing world. This is the crabbed, joyless, and ungenerous religiosity that Jesus spoke against: spiritual blindness.
Fr. James Martin, S.J., The Jesuit Guide to (Almost) Everything (Kindle location 526).
Surely, such a crabbed religiosity is not going to change the hearts and minds of non-Christians, whether they are atheists or Muslims or just indifferent or people recovering from various forms and shades of religious or secular fundamentalisms.
The ultimate goal of Christian relations with others is not to compare favorably with others--the ultimate goal is to win over others or, more accurately, to contribute in some way, however small or meager, to creating conditions in which the Holy Spirit can win them over for Himself. It is a grand mystery and undeserved privilege that God uses us in some way to create such favorable conditions for others to freely choose faith in Jesus. Such contributions on our part may include giving a book, speaking freely and respectfully of our own beliefs, just listening, or--a dimension that cannot be neglected--actually helping meet the legitimate, practical needs of others, material and otherwise.