We're built for running around central Africa in the heat of the day when any sane animal is looking for shade. Very few other animals have sweat glands over their entire bodies to dump as much heat as we can. Get outside of the 90° weather and we start shivering.
See the “Aquatic Ape Hypothesis”.
it has some good points on explaining WHY we developed the way we did.
Lets take it a step farther. Why is a duck still a duck? I againhave been told because it is perfectly suited for it’s environment. Why on earth would most sane creatures hang out in the shade, and yet somehow this “survival of the fittest” type change happened to make us run in the hot sun when the most sane of creatures wouldn’t? It just doesn’t make sense.
There is no evolutionary reason for humans to exist, none!