Hope- "it is the quintessential human delusion, simultaneously the source of your greatest strength and your greatest weakness."
We call ourselves rational beings, but 'to hope' is neither rational nor logical. May be that's what makes us human beings. "What an Irony..!"
Hope, Its the topmost thing in anyone's survival kit, even surpassing swiss army knife and a bottle of pure water.

What is hope?

It is one of the three theological virtues(in Christianity) along with LOVE and FAITH.
It is the human involvement on the future(on a time scale) emotionally.
Hope is not optimism, that is why I preferred to say emotionally, because optimism is a rational thing.
Hope is a beautiful "maya" to keep one going.
Many people find hope in a variety of things.
In god, In a poster, In nature, In the clouds in sky, In medicine, In food, In music, In People(parents, friends, teachers, students, colleagues, strangers, Sachin tendulkar), In words, In eyes, In a metaphysical force, And above all in the future.

Since Hope is more of a human thought,emotion... It is meant to affect or at least try to affect the events so as to bring the future to one's wish, demand or request. May be that is hope.

It sometimes seem to take the 4th dimension(time) into its hands. Which is not quite possible empirically. But I am not sure how it is influenced or affected; Through prayers, controlling cosmological elements and/or worldly factors. But it sometimes does get affected, few people call it coincidence(and they proudly calls themselves realists); few call it divine intervention; few call it the power of sub-conscious mind.

Whatever it is, We continue to hope.. The last resort of any wounded phoenix (before rising from the ashes)