An old woman was very ill. On her deathbed she asked her son to promise that he would visit her grave at least once a week. The son didn't want to disappoint his mother, so he promised that he would. But after his mother died, he didn't keep his promise. He was too busy. He didn't tell anyone about his promise, and he has never felt guilty for failing to do as he said he would. How do you judge the failure of the son to visit his mother's grave once a week as he promised?