Definition of "Friend"

Have you ever came across in the event when your friends contact you and inform that they are getting engaged or married something like that???? Understand that this is a very usual practice but have you ever wonder why does your friends would only contact you when they are having a special occasions and not during those usual circumstance.. Frankly speaking, I don't like this kind of bond!! Where were they when I needed them?? Sound ridiculous!! I shall not entertain at all!