I believe that a person's experience with attachment in their childhood has a major influence in their later lives. Whether they experience a nurturing or harmful childhood, this translates to an extent in their future personalities. But, I also believe that each person responds differently to their childhood attachments. For example, a secure individual can maintain their positive strong outlook on life despite hardships in their lives. Other people who had been raised with the same amount of nurturing and attachment, could loose this aspect in their personalities. Therefore, I believe that while early childhood attachments are very important in later adjustments, all cases are dependent of the individual and circumstances.
I agree that circumstances do need to be taken into consideration, as the theory cannot be generalized 100 percent to all individuals. However, I also believe that other factors can influence a person's well being later on in life, such as a decent socioeconomic status of the family, and whether the child has both parents living at home and giving their attention. Whether these factors are present also can contribute to a child's confidence and his development later on in life.