Every member of your family and each of your friends thinks the same of him/herself.I'm the smartest person in my family; I'm actually probably the smartest person in my group of friends.
Yes. But I'm also taller. Now as you go up higher the air is thinner, yes? So the taller you are the thinner the air is, which means your vision is less obscured, so your perception is better. Now, perception is reality, ergo my superior perception leads to a superior reality. So, I exist in a superior reality, if we recall the principle of "cogito ergo sum" - latin is a smart people language - then we can simply reverse it. I am in a superior reality; thus, I must think in a superior reality. Now simply divide the whole equation and you reach the only logical conclusion. Quite simply put, I think in a superior manner, as you can clearly see in my flawless logic.
Well, shorter people may have another intelligence factor that would effectively cancel out your thinner air theory. Less height means less length means less distance from heart to brain, so the shorter the person, the better the oxygen supply to the brain. But now that I think about it, if the heart is closer to the ground, it will have to work harder to push blood against gravity since the force of gravity gets stronger as distance to the center of the earth decreases. So I guess you're right. Sorry I misjudged you!