Conveying the ugliness of others from behind, is far worse than scolding him outright. No need to play cat. Although our dislike to someone is not necessarily true, we certainly have the right to deliver. As long as it is still in a reasonable capacity, of course legitimate.
If it is courageous and want to reprimand someone wrong, why just talk behind. The man who dared to talk behind just the same as a coward, talking behind is the act of a loser, dare not speak and rebuke in front.
Do not think it's a trivial matter, although it looks ordinary, things like that are believed to be a source of fire that can manghanguskan relationship two people. Whether it's on a friend or co-worker who happens to have an unfavorable attitude in our eyes.