Does IQ really reflect real facts about who think better? Or it's just another tool to fit people into expectations? If Einstein, for example, spoke about relativity in the dark ages then they will stone him to death or put him in a mental institution.

Seeing as the amount of people who take it for purposes of advancing their position in life based on their own expectations and those of whom they respect and hope to be respected by, probably the second. IQ at best is a measure of potential. I subscribe to the phrase, "put your money where your mouth is." If you have so much potential and don't use it, what's the point?

Seriously, are there such things as stupid people, or is it just some people do stupid things and at other times they do intelligent things?

However, just being smarter is not a gauge for success. Lots of people are smart and do absolutely nothing with it. And others are complete morons and somehow manage to run Fortune 500 companies.

"But don't you think that, in a way, they smart? They made it all the way to the top. This is something that not many can achieve."

You really don't understand how capitalism business works, do you?

What is "intelligence" and WHO gets to define it? …is a very important questions.

Clinically speaking, intelligence is the ability to make distinctions between different concepts or phenomena even if they are conditionally or functionally related. The more distinctions one is capable of making in increasingly less spans of time with increasingly accurate results, the more intelligent one is. This type of intelligence is testable and measurable and has come to be known as the Intelligence Quotient.

Now, there are also others definitions that are often applied to intelligence, but the above is the scientific and analytical definition because it is the only form of intelligence that is currently quantifiable, it is the most fundamental, and we have reasonably good information about from where this talent emerges in the brain.

Comparing between Einstein and Picasso, those are just subcategories of the same kind of intelligence. A different kind of intelligence would be something like artistic creativity which can't be measured.