Not having any guilt is a sign of sociopathy or narcissistic personality disorder. a little guilt is a positive thing. It is a sign of that a person's conscience is still alive. But if you feel guilty all the time, it is called guilt complex, when a person blames him/herself of wrongs they didn't do actually. It happens to over-sensitive people. It can be cured when you analyse the situation critically, and find that you have no fault in what has happened.