If, as a certain group posits, there is no reason for faith to exist in a world such as this, what is the point of trust? After all, is not trust an expression of faith?
You trust someone because you have faith in his or her abilities. In other words, you believe that the person you trust is more than capable of something, commonly shown when that person has you covered in many a given context--be it in the battlefield, amid an apathetic crowd, or even in a camp where the victims of intolerance are herded to be destroyed by murderous thugs whose evil can never be forgiven both in this life and in the next.
When you trust someone with your life, it shows that you have absolute faith in that person. The same thing goes with belief in a higher being. You trust that God or Allah or whatever supreme being you profess faith in has your life in mind.
Are you familiar with the term "test of faith?" The world as we know it is an imperfect one. In fact, the imperfections apparently give reason for certain people to deny the existence of a supreme being... Just say it: I'm getting ahead of myself.
Back to the imperfect world... Yes, it is a world where might makes right, where the strong prey upon the weak with utter impunity, a world apparently devoid of any shred of positive energy. Is it not a wonder why man in general has mixed feelings towards the existence of a supreme being?
If, as the nihilist posits, there is no hope for humanity, then the YOLO (You Only Live Once) philosophy applies. Let us eat, drink, and be merry, for tomorrow, we shall die. Let us try to do everything we can for the sake of pleasure in this nasty, brutish, and short existence those stupid religious dumbfucks who should all be remanded to mental institutions or extermination camps call life, because there is nothing else to it!
If, on the other hand, you believe that there is hope for the human race, you will most certainly understand that life...is worth living, for want of a better term. There is more to living than just waking up every single day to do your part in society and nothing more. There is more to life than the free-flowing booze, the insanely large harem, and the oscenely deep pocket that the hedonist sees as life's only purpose.
There is a reason Faith, Hope, and Charity (the last being the more theological term for Love) are considered theological virtues in the Christian context. Take a look around you. While many are apparently inclined to see the world as it is in the absence of faith (incredulity taken to extremes--trusting no one), hope (despair, cynicism), or love (intolerance, indifference), people embodying these three virtues still exist, extolling God wherever they go, loving one another. How else can one explain the "Faith in Humanity restored" meme?
I'm starting to digress again, am I not?
Faith exists despite the tide of nihilism because it is part and parcel of the human condition. Do you have faith? Don't worry, it's normal. It's something human beings like you and I are inclined towards having. Even if you disavow the existence of a supreme being, you still have faith--how else can it be possible for you to trust your neighbor? How else can it be possible for you to believe that you are loved, that you are not alone in this dark world?