Ultimately in life one is only responsible for their own actions, the thought and beliefs of others is their own doing. Not something you have to concern yourself with. Staying true to who you are and the continued striving to be a little better each day is all you need to accomplish in life. Others will say and do as they are going to, based on who they are or who they are trying to be. If you can't change that (and who says you should even try) then why should it matter what they think or say? Why should their words change you? Bulletproofing yourself towards other’s words is simply the realization that they don't answer for who you are or the things you have done, and when you realize that...truly...they don't seem to matter anymore...and their words become powerless.