Friends mostly become friends because of the common things that they share between each other as a result of those similarities they find themselves enjoying doing things together.
Even though friends are not similar but because they share most similar interest and love for each other they mostly enjoy spending time together which may result into them doing things at the same time.
The word affinity tells us that they have a very strong relationship because of their similar qualities which is what most friends share and what keep them together at all times and so does these friends above.
