For me it depends on the person asking. If its a relative or friend I am very honest. Not brutally but with tact. If someone asks me about their significant other I am very honest on what I think. If they ask me about an outfit they are planning on wearing I am very honest.
Let me give you an example of such an incident. Crazy, Clueless and I were in my car driving to a function we were attending. Clueless asks me what I think on the recent research that wearing bras can contribute to breast cancer. I told her that I think it's disgusting to go braless. It's tasteless to go around flopping in the wind and that little research wasn't enough to make me change my mind. Crazy pipes up from the back seat and says, "Well I think if it saves lives I'm not wearing a bra any more." I said," Eeeeiiiiwwwww! That's disgusting. I can never see just having the girls flopping every which way." She said, "There are cultures that don't believe in wearing bras." I said, "We are not there. We are in America and in America we wear bras." She got really quiet, I guess because she was mad that I didn't agree with her. I'm not the type of person that jumps on the bandwagon of every crazy research or fad. Come on now.
Another friend of mine told me what she was planning on naming her son when he was born and I immediately said, "Eeeiiiwwww! Are you serious? That is a horrible name." If you don't want the truth don't ask me.
On the other hand, if we are talking about clients or my bosses, then I might not be as honest as previously mentioned. That might not be in my best interest.
Are you always honest with people when giving them your opinion?
