Nietzsche's struggle for power can be applied, depending upon how far you widen the scope.
Words hit it on the head: survival. We are thrust into a state of existence of constant flux and for the most part we are wired to seek survival, there are ways to get around that urge (depression, despair) but for the most part we have to face and excel at facing our challenges (having power over them).
There are many different aspects of survival and our symbolic methods of thinking have evolved that concept into insanely complex networks of social structures, artwork, spiritual insights, etc, etc.
What is conflict? It is a challenge that presents itself that we can choose ot escape or to overcome, fight or flight. Now there are superpositions between the two that we often do in life. We are taught in social structures to be tactful, to avoid a state of constant trivial conflict in order to procure further advancement, a challenge that is larger in scope that requires organization not obtainable in constant chaos.
So the question becomes, what is conflict? When is it productive? What is truly best for human survival and advancement: individual, societal, and balancing the two? and what levels of scope are there that fundamentally have to be addressed in terms of adversity?
I am currently listening to a lecture from The Teaching Company on argumentation and it is incredibly interesting. The professor discusses how argumentation is a core foundation of social relationships. We seek to influence each other and our conversations are a form of informal argumentation at all times. Of course, you have to shed the negative connotations of unproductive argumentation that is so common among those whom don't understand the basic principles and efficiencies.
There are many different fronts on which we face adversity. We need them, and they need to remain in balance. Emotional, intellectual, physical, resourceful, etc, etc. We need to sharpen our skills, we need to increase our ability to survive.
In American society media seems to make us infer that materialistic (resourceful) survival is the key to happiness. What a load of shit! There are so many fronts that require constant exercise.
Think of sport, games, drama, romance, learning, they all sharpen our skills in some form or another. Any self-actualizing or person on the path to enlightenment will teach self-discipline, and the virtue of exercising and indeed conquering all of the above.
Increase your scope, grow your mind, strengthen your body, love your friends, prepare for the drought, be psychologically ready to console or to war.
Our bodies and minds are tools, they need to be sharpened and our own biology tells us this.