As an old hand told me, it is life by the braille method... You feel your way through, and some times the emotions speak better truth than does reason...There is a time to take council of your fears, and of all your emotions, and that is most of the time...
I find this 'braille'-idea a very brilliant way of describing it.
I have to add that much of what is seen as intuition is actually recognition by instinct.
We should distinguish that.
For example in Kroni's OP:
You see a person and just sense you shouldn't get involved with them.
Nature has equipped us with a lot of knowledge about how to judge situations.
Many are based on perceptions that are not conscious: Body language and size of your oponent, etc.
All of that is information processed instinctively.
Intuition however acts on a more complex level.
The way i see it, it's a kind of intelligence which is opposite to analytical intelligence.
As oppose to dividing something into its pieces intuition is based on putting pieces of a puzzle together.
Intuition is often based on information you receive but also on what you don't receive.
For example you enter a restaurant and you have this feeling that something is missing, like people just don't talk. There is no conversation in this restaurant.
Classical movie situation.
You will probably not stay for too long.