I like him/her

Have you come across at a job fair or at a work place phrases like "I like him", "I like her" flying by your ears? Well, one may not pay attention to such common conversations but do you know that it can be a major decision making gesture, specially if those the phrases are coming from are the powerful people in that organization or a group? Yes, one's likability has become a matter of hire or fire just like a love affair is a good example of that. Those who got lucky usually like to proudly claim, "Oh, the boss likes me" or "I am very liked in the work place". So, the easy conclusion to be made is that there is probably 99.9% weight given to a person's likability to make a hiring decision. Because of those facts, I may be tempted to conclude that likability can be a very crucial component for working with people. It is not an easy comment to swallow if your coworker has gathered his/her composure to openly say, "you are hard to work with". Does that mean indirectly, "I don't like you?". Of course, but it depends on who says it. It is good to be liked and it is even better to be fun to work with too. There is nothing wrong with that. If one encounters such challenges, self improvement techniques are a good way to go. The problem though lies on how to define likability. How about being hard or easy to work with? Is it a natural phenomena based on instincts or is it as limited as the size of a typical company? I wish there are thorough researches made on such a broad subject whose outcome affects all of us in many ways. Recommend any book?