To say or not to say

I have this long-standing discussion/argument with YQ. (Fortunately, we embrace the aplenty differences between us.)

She thinks that friends have a duty to tell each other, things others do/say behind their back. Her purpose is to remind friends who are their true friends and let them see people's true colours.

I think we will never really know another person's real intention and informing others' of happenings we saw behind their back, only make things worse. The situations are not always black and white.

Who are we to judge what others have done and said? Furthermore, we probably added our own judgment to the situation. The ideal is to relate incidents objectively and having the listener taking in information objectively.

Just how possible is that? So I say, silent is golden.