That system breaks down if you start dating from within your social circle (friends of friends). I know you'll tell me it's a big no-no but you'd be surprised how much more common it becomes as you get older
Very true. It becomes harder especially if the breakup is messy. As a friend you are forced, like it or not, to choose sides. As a person in the relationship, you are in the awkward situation of knowing that some of your friends are going to side with the other person and so on.