Take the mathematical proof for a boundary of a boundary = zero, then add to that the concept of syndiffeonesis which essentially states that any 2 relands x and y are always embedded within a common syntax and so all relationships are syndiffeonic relationships, and you will see that the concept of an "individual" is really not that simple. In fact, these two concepts alone are enough to throw anyone's idea of "self identity" for a loop.
Then, there is the idea of pride. Pride is an extremely dangerous concept, especially when that pride is linked to some endowed characteristic such as your ethnic or cultural heritage. If you are proud of what your forefathers or your ancestors did, don't be. You didn't do a goddamn thing and there is no reason you should be proud of something you didn't do. The idea of pride is one of the root causes of the self-vs-other paradigm which leads to things like nationalism and racism (the two are not mutually exclusive).
Having pride in something you DID do is a different issue, but it is still a touchy subject. Can a person truly act alone to commit an act that he/she can be proud of? Or is one's ability to act itself a result of interdependence? I would argue for the latter.
Sacrifice is beautiful because it mitigates the ego. When you are focused on someone else, you become selfless and compassionate. As you are part of an interdependent system, acting selflessly and compassionately indirectly helps you. Nature is about give and take and balance. The thermodynamic law stating that energy cannot be created nor destroyed suggests a "zero sum game" as you put it. If you look at nature, you will learn all you need to know about how to live. Animals and plants take, and animals and plants give. If you are unhappy with the current state of the world, maybe you need to sacrifice MORE, not less. Those who take and take from nature will not be given the same amount in return.
Edit: OP, being a human being is no more important than being a spec of dust on your mom's toilet seat. Are you proud to be a human being? Why the hell should you be? By the way, the only argument I can think of that would give credence to the idea that human's are more "valuable" than anything else is due to the energy involved...we all know that it's better to eat a single cow because that cow contains x times the amount of energy of a single fish. Thus, the cow has more energy to contribute, and thus more energy to give. But actually...doesn't this suggest that sacrifice becomes MORE important as you climb higher up the food chain?
Edit 2: Sacrifice is a sign of strength as it takes strength to sacrifice. If your ego hurts when you sacrifice...then your ego is weak.
Your concept of pride, interdependence -- love, it's all just a result of a feeble human intellect trying to justify its existence. There is no meaning. There is no purpose so why try to tie yourself to things so insipid and artificial? You're merely tossing salad and eating it too; fiber that lacks any benefit other than to move the nutrients and energy that keeps you alive: You can't even stand to live without your artificial moral constructs. No wonder you don't understand where I come from. You're no individual. You're a shell; a means to an end. Feel free to be as such but you won't force me to play your game.
Heh and you define utilitarian resources such as energy as what makes life. You make me sick. Life is not defined by its consumption but its choices in perception, in what it chooses to value, the resources it chooses to grasp whether it be the coercion of its own existence or higher-level pleasure. No concept, no religion, no artificial meaning can change the force and value by which organisms sustain. I choose to accept these selfish desires and its by no interdependence that one chooses to create and thrive: it's by ones choosing and feeling alone that an action is made. Multiple individuals cannot act and feel unilaterally. One may exchange with others to achieve their ends but this debt was paid as it was made. No slavery is obliged.
I never implied importance nor entitled value from mere existence alone. I am only the value people wish to grasp through whatever means and the value I bring myself through my choice to sustain. I am a man of choice, Mr. Joint. I choose to value myself and others may choose to value me. To force me to value something I don't wish to value, that to me is sacrifice. That to me is slavery.
Those who succumb to the whims of others and their definition of value unilaterally... that's weakness. That's no choice at all.
A man chooses. A slave obeys.
Again value is choice. I'll achieve what I want through whatever means and that may be through valuing other people. That's not selfless and that's not sacrifice in my book for I suffered no loss. No loss is no sacrifice. Feel free to stroke your ego by giving it terms such as sacrifice but I won't stand under it.
To tell me genuine sacrifice, death and destruction is virtuous under pragmatic and religious pretenses -- that won't alter me any. There is no god, there is no sacred purpose besides what an individual perception values.