Reason is meant to serve the Will

For millennia humanity has been thinking about the meaning of life, religion, philosophy, freedom, love, but it seems to me that before thinking about any deep subject it is important to understand the relation between reason and will. Reason is serving the will, and will is basically the maximization of happiness/ minimization of unhappiness when taking into account all the factors.
The more reason and understanding of the world one has, and the more self awareness and introspection one has, then the more one’s reason is at the service of one’s will. I.E, I want something, and will use my reason not only to try to obtain it, but also to try to foresee the consequences in order to know whether I will still want it.

Why do people do good? Because if they don’t, they will feel guilty. But does it mean that a person does 100% of the potential good that they can? Suppose for simplicity that a person feels guilty if they do less than 50% of the good that they can do. But if G-d has a standard which is 80%, and will punish that person with some punishment other than guilt if they do less than 80%, than that person will do the extra 30% out of fear of this punishment.

A parent that sacrifices their life to save their child does so because they rather die than to suffer the sadness of losing their child. Reason will tell us that this is an instinct that nature imbedded in creatures in order to preserve life and it is therefore some fundamental natural design. But does the parent really care? All that parent cares (and therefore feels) is saving their child.

Suppose G-d appears to a person and tells him the purpose of existence. Then the person might say “so what”? Suppose then that G-d says that since he created that person for some purpose, in order for the person to fulfill that purpose he possesses an inbuilt attractive force in the form of an utmost happiness when he fulfils that purpose. Knowing that he will feel that outmost happiness, the person will be driven to act in a certain way, but the reason why is it so BY ITSELF won’t matter to him, but will serve only as a “guide”.

So when humanity asks all these deep questions what they are really seeking is that "guide".