Forgive and Forget (I cant do both !!!)

It irks me like hell that I cant forgive people easily. I can ask for forgiveness easily and actually convince the other person to forgive me usually (don’t know if the person does forgive me from heart but I try my level best) BUT when it comes to forgiving somebody. I don’t ! I never forgive people easily. WHY ?
Why is it so difficult for me ? I cant seem to forgive people for being dumb or insensitive!
Suppose person A is very dumb. Everybody hates person A because he or she is one of those irritating kind of person who gets into a good position by mistake or lady luck And I know person A is dumb. I know person A has been sent down on this Earth to makes other people’s lives miserable. So if person A does something stupid which involves me it should be easy for me to forgive him and her.

No , its not ! Im still fuming…