Only because emotions are ruled by the brain, brainy people ruled over the emotional ones over and over again throughout the course of history. People of brain logistically calculated things, in their own ineterest, to the other's loss, to obtain power and grow.
Emotions that lack brain power are dumb and stray cattle having no one to govern them, and brains without emotions is like that farmer without land or cattle. Who can survive alone?
A simple look at philosophies around the world would make us aware of the people who lived then, when we see philosophers in the west explaining things rationally with clues of (khuraafat) assumptions and on the other hand witness places, mainly far east, we see lesser emphasis on rationality and more of an emotionally intelligent quotations, enlightening the heart and guiding the mind, and at the same time clues of (khuraafat) assumptions.
In India it's like a lot of baseless story-telling and at the same time having a little bit of rationality and a lot of emotional values. Why emotions more than rationality; because if you have many assumptions and fictitious stories to tell then it's deffinetly due to the loss of most of mental/rational guidance and with the availability of much of emotional values that would govern the mind through the love, hate, praise, etc. qualities.
I'd explain that here, in India if someone is loved or praised for an act, instead of being percepted by a rational part of the mind it's taken mostly (in such a rate that overlaps the requirement to remain in balance) emotionally, and that causes the extra given attention to touch the 'excess'. This system then leads to a beyond the human limits of love and then the person that's praised a lot is taken as a god (being nothing but just another human being)! And if hated, then hated to death that no matter what punishment would incur later (and that's something only rationally visioned in the future) they would pursue harming the person!!! Keeping no limits in mind as a limit, and all means as a mean.
There's another group of people that have them in balance, they are rational and emotional in proportions so close that neither they're carried away by emotions to an extent defying rationality and are thus under control when they approach an access, while no so taken by being rational that they wouldn't conside emotional importance in life. In the Quran they're stated as (ummatan wasataa) which stands for a sect of people that stand in the middle. Map-Wise, phsychologically, etc.
These people were at a time more emotional than they should've been (in the abbasid period) and focused on leisure and got lazier than they should and failed. Never got up since then.
A rational warrior in the battlefield would come with most advanced artillery and wouldn't have an emotional content strong enough to stand the adversities of war, people at home would be petrified if something had happened to them and wouldn't know how to handle that and have to visit many doctors to psychologically (if not otherwise) get checked; while a warrior who's all emotional, all set to fight and proud of himself, full of patriotism etc. etc. and hasnt' what the brain people developped, would surely loose and there's no doubt at that... But the warrior who neglected none of the above, has worked on his needs rationally and planned for the war, and is all full of excitement and is motivated and partriotic in his approach would surely attain victory (by the grace of God) under the laws of nature.
No matter how we'd approach things in life, we can do that either mostly emotionally or mostly rationally (there's never a pure emotional approach or a pure rational one, even if it contains 99.99% of either one of them). And to make us take the step this one way or another there's the element of love or lust.
No matter what the drive, and no matter what the approach, the most success is attained by those who chose it in a rational way, and the least is achieved by a blind yet willful way of the emotions. Again, neither one is complete without the other, but yes there's one ahead of the other and one below;
Imagine that you have a building, your office is upstairs and below is a lobby for wellcoming. One would say the office is the head and that's important, the other would say that (and it's really a sensible answer) how could you have been to the office if you didn't get a positive impact from the lobby you've been through!
Yes, it's that way. If your being rational rules over your being emotional you'd attain a successful life and otherwise, you're gone...
