Codependency is not necessarily a bad thing. However, when you’re doing all the work and suffering all the consequences, that’s too extreme. The goal is to strike a golden balance between not being firm enough and being overly harsh and uncaring.
The main effect of not being assertive or having poor boundaries is that it can lead to low self-esteem. If we never express ourselves or conceal our thoughts and feelings, we can feel anxious, resentful and have uncomfortable relationships. We feel like the people closest to us don’t really know us and fear that being assertive means that we’ll be too aggressive or that others will reject us or react poorly.
Assertiveness means being able to clearly and calmly express what you need without being overly passive (hurting your own self esteem) or aggressive (damaging other’s self esteem). Communicating assertively doesn’t guarantee you will have your needs met. However, it does make it more likely that you will be heard and listened to. It can also dramatically improve your relationships with other people in unexpected and beneficial ways.