No one truly depends on themselves, "I", throughout their life.
No one is unaffected by the other humans inhibiting the planet.
"Self" confidence is a fallacy. Everyone's perception of who they are is constantly influenced by other people. There is no such thing as "self" confidence.
Everyone needs love almost as much as they need water and air; so there is also a natural desire to be valued in all of us. Even if you claim to not care what other people think you still have the desire to be valued by someone or something that you like. If I am a Lady Gaga fan, I will be hurt to find out she has a negative perception of who I am.
It is not about "not letting people get to you" or "giving them the power to upset you." If the insult is heard, any negative feedback is received, or rejection is experienced from others it does in fact affect someone. A majority of people refuse to admit this which is a defense method. It changes a person's behavior to know they are not loved, accepted, or acknowledged. These changes can be very severe and even costs a person their life.
Social anxiety, depression, low self-esteem, and aggression are just some of the most pre leant tragic behavioral changes. When someone is rejected by the other people in their environment and feel like they don't belong it becomes harder to reach self-actualization.
There is not point of human existence where "I" is said to be sustainable. In the Bible at the very beginning as soon as God made man He made him a companion. God said Adam was lonely; we are built for each other.
Human minds are like clay; able to be molded by what surrounds them. Your mind is molded by what you observe in your environment. We all experience human company at some point in our lives. Others reactions towards us, no matter positive or negative, influence the way we see ourselves.
You may say that you don't care about the person trying to hurt you. Inevitably there is a hit taken to self-confidence even if you do not immediately realize.
Honestly think about it.....
If neglect, negativity and rejection truly did not bother people many factors of our culture would not exist. Factors such as beauty campaigns, social anxiety, mass shootings, suicide hotlines would not exist either. Not only do they exist it they are a prominent part of our society.
As someone with moderate anxiety I can say from experience that neglect has certainly changed my behavior for the worst.