Definitely No. I believe people who hold on to resentment are hurting themselves a great deal and they usually don't even see it. They're poisoning their mind and bodies with stress and negative feelings and they're holding back the happiness and contentment and peace of mind that could be theirs if they could only get rid of the clouds and the walls that are holding the positive things back.
It is not easy to get rid yourself of resentment, but always remember - the person is going through a great deal of pain him or herself. As Longfellow says: "If we could read the secret history of our enemies, we should find in each man's life sorrow and suffering enough to disarm all hostility." Or resentment, I add.