There are three basic truths about friendships that need to be understood.
Friendship is a Choice between two people.
Friendship is a give and take relationship.
Some friendships end.

You and the other person both have a say in the choice to be friends.
When you are being intentional you are taking the first steps in developing the friendship.
When you are being intentional in your friendships you are protecting your friendships from ending prematurely, and you are calculating when your friendships have run their course.