What is shame? Why should you be ashamed of?

I know i didnt do anything wrong.I have done everything possible by my four limbs,even though i hear "You should be ashamed of....."; May i ask why? I ask why from myself........ 

Shame;when do you feel it when your own conscious knows you have committed a sin,mistake or offence which you could have avoided or could be corrected. Self realization of shame is humiliating and always pinches your heart. But when your caregiver's feel shame in referring to you or your present working status....Its just not humiliating its dyingly painful."What to do ,how to make them proud " when these are the questions first on your mind,rather than your own selfish enjoyment. Is this the moment after which a normal happy go lucky person commits something outrageously stupid....I can really feel that emotion quite strong today....... 
After today it would be very hard for me to say that "Whatever happens happens for good?" if you cannot make your folks proud .......... may be nothing happens for good its just a feel good statement nothing else..... 
Your world really crashes down when you hear something from people you not only adore but you admire the most,When all your attempts of making them happy goes to just trash........... 


But then again somebody has truly said that "being ashamed of yourself is a criminal offence bigger than committing a murder".