What Makes a Hypocrite?

What makes a hypocrite? Does filtering your thoughts before speaking make you one? It is all really confusing to me. On one hand, I would have loved to let the things off my chest and get instant relief. But on the other hand, I too know that regret will follow the relief after that.

I wonder if others face the similar dilemma or am I alone in this? 22 years of living didn't seem to teach me enough about handling such situation. Or perhaps I am a slow learner in this area.

So, which one is more preferable?

Brutal honesty or restrained expression?