Like my friend once said, it's better to be a front-stabber rather than a backstabber. You don't want any weaknesses in your friend to be there forever, but you just keep quiet, no action. You just live with throughout your life coping with that, realising that in the same moment, his actions to you could be worse to other people. In other instances, you want to confess about the things that you keep in your heart - your thoughts, and opinions about that person - all this time, not daring to say it out loud, fearing that your friendship with that someone would be strained, and eventually end mercilessly.
If you do that, that is what I call merciless.
A person who tells whatever he thought to his friend for the sake of making their relationship stronger is valiant, deserves to be applauded. Sometimes, it's good to be told about our weaknesses in front of our face. It's bitter, of course it does, but that bitterness teaches us that life is sweet at most times, we need the bitterness to let us know that we're not saints, devoid of defects. Think again, those faulty things in us are the things that empower us to change to a better us. We would still be the same and think that we are faultless without those front-stabbers. Period.
It is, really, up to us to accept what they'd said. If that friend is really your friend, he'll accept it, ask you something about it, and wouldn't mind about what you said. He'll try to find his mistakes and improve on them, because he know what you said is on a good note. A lot of times I'd been through this - I thought that they were wrong, I was correct, I just couldn't understand why they would do that to me... but, I thought wrong. They were right. I was being too selfish at times. I mean selfish to not really understand how to be a good friend. I tried to change, and still trying. I can see large differences between the past and the present. Let's hope it will continue, shall we?
We're humans. I'm one [totally]. We're imperfect because we are born to learn from those imperfectness.
Sweet lives ahead~!