Whats your end game?

Recently in my ethics and values class we discussed the writings of Kai Nielson and his arguments on morality and religion. Nielsons makes it a point to empahsize that, if one's sole motivation to take any moral action is to obtain an eternal reward from a god or gods, they are childish and weak minded, and that there are deeper and more profound reasons for living and being.

I'd like to argue that there aren't. Not just in the aspect of religion, but in general.

One of newtons laws states "for every action, there is an equal but opposite reaction" is this not fact? Is this not a fundemental law of science? If it is indeed a law of physical science, is it safe to say "action reaction" is a law of human science and or behavior?

Give me an action, I'll give you a reaction. Give me an action and i'll give you an end game.

I eat for energy and pleasure.

I use the bathroom for relief.

I work for money.

I attend school for a chance at a better career.

Etc.

Every action has a reaction. Even Nielson has an end game to writing his essay, Nielson writes to make the religious look childish and selfish. But his action, whether he'd admit it or not, is motivated by the estimated reaction. So, is he, by his own logic, selfish and childish aswell?

Even quote, unquote "positive action" is motivated by the reaction.

I buy my wife flowers to make her happy. (and or to get some)

I practice moral behavior to feel like a moral person.

I treat others well so that I will be treated same in return.

Action, reaction.

So class, whats your endgame?