the "end" in friend

When it comes to friendships, are breakups necessary?

AskMen has this article about how to end a friendship. Recently, I heard a story from someone who received a phone call from a (former) buddy formally ending their friendship.

Assuming you've made the decision to sever ties with a friend, does a lapse in contact suffice? Or do you need to explain your motives?

Looking forward to hearing your thoughts.