When it comes to getting to know someone who has the potential to be a friend or a lover, it is not always easy. During the early interactions, there is a tendency for people to show their best selves. To present themselves in a way that is different from how they normally are or to exaggerate how they would typically behave. And unless one has a good ability to read people, a sharp intuition, or has done a lot of work on themselves and therefore, generally attracts healthy people, it can be a bit of a mind field. This means that looking to other sources can lead to insight and to a better perspective on what someone is like. One of these sources is the friends that the person has.
While this can relate to all of the friends that a person has and spends his or her time with, the most important friends are typically the ones they are closest to or spend the most time with. Casual acquaintances may reveal certain pieces of information but not as much as their closest friends do.