It is highly probable that a lack of assertiveness has meant that you tend to go along with and agree with another’s thoughts and feelings. This can result in you feeling weak and that you and your feelings are not worth a lot. Sounds a lot like depression, doesn’t it?!
You might focus on pleasing others, to the extent that you feel unfulfilled in your own life. Worst of all, this inability to relate to significant others may well have a detrimental effect on your personal relationships.
On the other hand, being too aggressive can lead to the loss of relationships, or the inability to make new friends. Once again, this could have a detrimental effect on self-esteem, as there is a tendency for the individual to blame themselves in these situations.