Deffensive Mechanism

I have a pretty effective defensive action when it comes to friendship. But it's not easy to practice it. You'll feel like u're taking people sincerity for granted. It'll also take away ur sincerity. But for me, if i can protect myself, why not i just do it. True friend are really hard to get, but i think i found some, n i'll treasure them. Since then, my self-defensive mechanism tell me to stop open my heart to other people. That's what you learn from being hurt in earlier days.