Intelligent people are recognised mainly by their:

* in childhood and teenage-years; by their high intellectual interests

* their tenedency to correct the teacher without asking them politely, if they did something wrong the intelligent person just finds stupid.

* their tendeny to avoid small-talk because for them it’s only a trivial talk and a talk about people.

* Tend to almost allways focus on ideas when talking to others. Instead of asking their mates: “Can we learn toegther at 5 o’clock to repeat the topic of the university? It’s so boring”. They say: “Isn’t it stunning how the inventor came up with this defintion? Would you have used this one or would you have thought of another one. If so, which? Then I tell you minde!”

* Are often considered “lazy” because most analytical things come naturaly to them.
are mostly overthinkers.

* Are solution oriented rather then dwelling on a problem.

* Can quickly find the main idea in an essay.

* Can adapt to new (analytical) situations quickly.

* Can learn to think outside the box.

* Are curious most of the time.

* Prefer to be single or live with an intelligent partner.

* Value ideas often more than people (because people often feel bad when recognising these ideas aren’t from themselves. More, see below!)

* Tend to have friendships (almost) only with people with similar intellectual strength.
Are virgins often much longer than the below average person.

* Almost never live in the moment (because they tend to see their emotional world as “rather primitive warning signals of stoneage needs”)

* Their confidence is much more often displayed in their verbal communication than in the - much more important - non-verbal communication which makes them ineffective dominant people and as a consequence often unwanted in a sexual relationship with attractive people.

* Are often much less happy than what most people would expect.

* Can only feel happy when (intellectual) challanges occur.

* Hate routine problems.

* tend to value intellect much more than physicial appearance. 

In the following remainder of my text I must say that I really only use constructive criticism to some answers here, I do not have the right to critisise negatively anways.
So, a lot of people wrote an answer which has following flavor:
> “Intelligent people are self confident but modest”

Unfortunately this isn’t true for all, only for some. If intelligent people were really confident a LOT of world problems just wouldn’t have taken place (financial crisis happend because the intelligent people were NOT obeyed. Forests important to our lungs are cut down because some people had it hard to understand the photosynthesis in school and are now leaders, etc.).

In my university the most confident students - those who believe get all A’s - are most often those who totally fail. I have no right to talk bad about them because they simply aren’t talented and can’t see the lack talent. (See Dunning Kruger effect)

The saying: “The problem with the world is that the intelligent people are full of dobts while the less blessed ones are full of confidence” [Charles Bukowski] wants to tell us that the people who have a genetical advantage from birth tend to find so many things so easy that they think everybody must be able to do it and overestimate the power of their peers and often make other people feel bad about themselves because they often can’t keep up to their high standards and therefore start hating them. This causes missunderstanding in the intelligent people and they feel like outcasts and start to socially isolate themselves and only mate with likewise people. It makes them sad because deep down they actually want to feel needed by ordinary people too but they also don’t want to “act on their less high level”. This causes feelings of frustration at some time and keeps them away from social confidence and true happynes.

Our best professors in the university are often those who are most surprised about their invitations to other universities and allways think they “just don’t understand enough”…