I think my best friend needs to have same code of humor. We can talk about any topic for a long time. And both of us can feel comfortable and funny. I often feel shy when I meet awkward people. So I try to talk with them excessively to break up awkward mood. Then I feel tired quickly. But when I met my best friend, I was very comfortable not to do something. Frequency of meeting is important to make a best friend. I can feel awkward to her who was my best friend if we haven't met for a long time. Because if we haven't met for a long time, then we don't have something in common.