Why are we so defensive? It's more than fear, miscommunication, or intimidation, but those all seem to contribute. The trick is to not let your defensiveness prevent you from listening to the other point of view.
I'm here partly because I was defensive about my "social network." I was complaining about mine and was told, "you need a new network." While that was true, the reality is that my social network of years past had become so successful that it was interfering with work, family, and other fun. At that point I cut the best part of it off completely for several years. Like most everything else in life, the key is taking all things in moderation.