Have you ever wanted to give your boss a piece of your mind?

I have had issues with my boss and I have wanted to tell him what I think. I have not told him what I think due to consequences I might face. Some of the things he does makes me mad and I think it is unfair and don't think is right. I want to speak my mind but afraid too. I really don't like being taking advatage of. I believe in being a fair person and to be he is not fair alot of the time. He even takes advatage of his authotirty. This is not in a good way. It make me and alot of others mad. If it happens again I will be talking to my big boss. I have hinted and said things to him to make him relize maybe he is doing wrong. It has not worked yet but I do admit I have wanted to give him a piece of my mind.