Whatever our purpose is being friendly should be part of it. However, there are those we should mentor while others we should have a friendship with.
We can actually be a mentor well as a friend at the same time. Often mentoring comes out of friendship. I would call it the next step.
The whole thing though about our purpose in life we should do more of caring than out of doing for the gifts and talents we have. Other words we should not do something because we want to have points added on by doing works. We do all things for the greater good of all involved.
We all need friendship besides being friendly. It doesn’t mean we will gain friendship with everyone we are friendly too. The reason is we don’t have the time to be friends to everyone we meet. We can be friendly when we see them but there are those we will be friends with too. We have to see who they are and act accordingly.