Tim Kreider said this quote

“ Society doesn't officially recognize friendship as an institution in the way it recognizes sexual relationships, so there's no real protocol for ending one. If you've been going out, dating, or just sleeping with someone for even a month or two an you want to stop seeing him, you're expected to have a conversation with him letting him know it and giving him some bogus explanation. This conversation is seldom pleasant, and it ranges in tone from brittle adult adult discussions in coffee shops to armed standoffs in day care centers, but once it's over, you at least know your status.Because there's no formal etiquette for ending a friendship, most people do it in the laziest, most passive and painless way possible, by unilaterally dropping any effort to sustain it and letting the other person figure it out for themselves. ”