Is ignorance bliss?

A common phrase we hear as a child is "Ignorance is bliss."  But as I have grown to become an adult, I have learned how false that statment is in certain situations.  The not knowing about something can often times hurt the outcome more than knowning even the smallest piece of information.  Dont get me wrong, there are situations where the not knowing has it place, but that number has become smaller and smaller.  The only time I could see not knowing, thus ignorance is bliss, is when there is a stressful situtation at front and the information another individual has has nothing to do with the situation and would cause more stress.  Then ignornace is bliss.  But in any other situation I do not see how not knowing benefits the person making the decision.  If the person enters blindly into the situation, then they could make matters worse because they would be acting in the same manner they have always acted. 

To often it seems that people believe that people are mind readers which is ironic because if people were mind readers, then those same people who wished people were mind readers would be upset.  A mind is a sacred place because its our private santuary.  No one can read our minds.  True a lot of time people can read our emotions through our facial expressions or our eyes, but they can never read our minds.  Which is what annoys me about people who expect people to know what they are thinking or feeling with out rightly telling them outloud.  I get that we should learn to read peoples body language or facial expressions or moods, but all that can be deceiving or if read wrong lead to a big mess.  I don't have an answer to this problem I see but I guess its a live and learn process.