One of the greatest quotes on friendship is, "show me your friends, and I'll show you who you are." People often underestimate the importance of developing a strong circle of allies. As a result of humans being social animals, people tend to aim for quantity over quality in the arena of friendship. However, friends do more than ward off loneliness and help you pass the time. Friends can subtly shape your behaviors and beliefs if you let them.
The entrepreneur and author Jim Rohn famously said that you are the average of the five people you spend the most time with. You can question the depth of the veracity of his quote, but there is at least a kernel of truth that lies in its core. So much so that even the Buddha expressed a similar outlook on selecting friends. In the video linked above from Freedom in Thought's YouTube channel, the Buddha explains his perspective on forging friendships.