What do you think makes good friends? Season 2: college period of Sar

I have been always thinking why some people are born friends just from first sight.
Actually I have no answer for that but I am glad to see that my roommates are such friends of me.
Since the major I chose in SCU is really not something for girls, there are only five in my 40 class. Maybe someone meeting another is not a scene in drama, for we girls were like in the moon. Math-majored girls only cared about what the courses taught them and how to finish their homework well. We didn't talk though in the same dormitory.
Sar seemed no difference at first. She is someone performing the same way as other science ladies. She can read tough topology when I was playing cello and Harbeby guitar. And she would respond to my question after such a long time that the rest of us came to the next. She is also the guy that laughs when others finished doing so because of some math problems staying in her brain. She is quite weird to us but we became best friends! I can't remember how it happened, but I keep in mind that we understand and love each other. She still a girl regarding what is happening around but she would laugh and talk loudly with us. She becomes good at joking and kidding about some popular topic that was not her taste before. She is totally someone in our world. At the same time, we learned to respect each's way to do things. We are so closed and having own privacy.
Sometimes a good friend is some person you can talk to about your personal problems and who can comfort you no matter what the problem is.