It's not fair. You may have met them at a bad moment. For example, just before a surgery, after they were fired o on a day they were ill and couldn't do the ironing.

On the other hand, our instincts that warn us are usually accurate.

Agree with Tinkerbell. The book "Pride and prejudice" had talked a lot about this topic.

We have a saying that goes "Don't judge a book by its cover." So if you only see a person from the outside, you cannot know their personality and attitude for sure. What if you meet somebody who looks really intimidating, but turns to be exactly the opposite; kind-hearted, humble etc.? Then it would be unfair to jump to conclusions because it seems like prejudice.

Yes it is fair.
Amount of information one gets form a single glance is well above zero:) You just need to be accurate with this information:
- she is red-haired. Or she has dyed her hair red. Anyway, she probably loves te be red-haired... Sometimes.

Like this.

At the other hand, it isn't fair to judge people you know for millinia:) First, it isn't quite good to judge people at all. Secondly. to <em>really</em> know someone is one thing, to know him for years is other.

Probably not, but it's in our genes - basic human instinct. In ancient times, if a horde of invaders descended on your settlement, spears and flaming torches in hand, you didn't have time to hang around waiting to find out whether they were actually really nice guys deep inside. Gut instinct had to do.