Humans have this strange behavior: Some people like other people which are disliked by a third party of people. But there are also people that are generally disliked by most ofthe others.
Let me make an example:
Person A, B and C like Person D Person B, C and D like Person F, but A hates F Person A, C and D like Person G, but B hates G Person F and G get along well with C ...
How can you explane this strange behavior?
Some people can't get along with each other, but both have common friends, that get along with both of them. So it can't be like that they are so different from a cultural standpoint, because they have common friends that get along with both.
Do you get the point?
However there are people that are liked by most of the People and there are also people, that are commonly disliked by the majority of people.
What are they doing right/wrong?
If you say, "people like those who are similar to them", how can it be, that A and D don't get along, if both are similar to B, which can get along with both?
What are A and D doing wrong, so that they can't get along. Due to the fact, that B get's along with both, which means, that both aren't bad persons and people you can get along with.
Can you generally say what makes the difference in these groups of people? Where do these preferences come from and why do some not get along? The question is not, what makes someone likable (that is asked here What makes you like someone?), it's more on how to determine wheter two people like eachother or not, on what is this based and can you influence it.
Is maby, the way people get introduced, a factor? What are the big factors
As mentioned below, the question might be rephrased to: "How can you describe this behaviour"? (I don't wan't to boil it down to one factor (and it's probably impossible to list all of them), but I would like to get a general Idea, on how this works.