Only people with the toughest of exteriors can claim that they take absolutely no notice of what people say to them or about them. In fact I would go so far as to say that nobody truly doesn't care. They may put on a persona that suggests they are immune from criticism but when they have the time to reflect they will still take on board some of what has been directed at them.
Generally speaking we can't help but absorb something of everything that happens to us during our life.
Negativity, praise, encouragement, insults, you name it and it will have some effect on you, and as more and more time passes the effect can be multiplied, especially of what you are absorbing is predominantly negative.
Imagine a child that comes home with a report card full of A's and their parents berate them for the single B they got. How about the person that goes out of their way, at great personal inconvenience, to do something they think will be appreciated, only to be faced with negativity or a complete lack of recognition.
If you want to take a more extreme example, how about somebody in an abusive relationship, constantly told that they are worthless or at fault for everything that happens.
There is a saying that if enough c**p is thrown then some of it will stick. And that's sort of what goes on through your life.
What do you expect a person's opinion of themselves will be if they have had years of being told they are rubbish? For a lot of people they will start to believe it. It almost becomes a mantra that they live by. They try something, it goes wrong and they say to themselves, "What did you expect? You're rubbish". Or they won't even try because "What's the point, you'll just muck it up anyway".
This can manifest itself into a person having extremely low self esteem and feeling they are almost worthless. This can start to get extremely dangerous for the individual if there is nothing or nobody contradicting the negativity.
It makes a difference just to have someone say "I believe in you" or "I'm here for you, just give it a try".
For some people the self loathing is so ingrained that they treat positivity from others with suspicion. It's so unusual to be on the receiving end of something or somebody good that it's almost as if their brain cannot comprehend the new phenomena. There must be some ulterior motive behind it.
But it's not all bad news. There is something that can trigger significant change in a person's outlook and self opinion. Plus there is even better news. YOU have full control over whether the change can occur or not.
When you're telling yourself how rubbish you are, it's your voice. It's you telling yourself that it is true. You have come to the conclusion based on evidence provided by others but that doesn't mean the evidence is reliable.
Remember that child with the great school report? What if, years later, they were able to look back at the event and tell themselves "You know what, I was pretty damn good at school". "I don't care what was said I'm proud of what I did".
How about the person that did the good deed? So what if the recipient was ignorant. They know they are a good person who did a good thing and that's what matters.
Of course, it's not so simple as to just tell yourself you're great and everything is suddenly fine, but that is where effective counselling can help. Over a period of time a person can look at how they are, spot the parts of themselves that are preventing them from being as happy as they could be and, with help and support, try to identify the reason why they are how they are. Then they could be in a position to realise and understand that what they have done is listened to other people ahead of themselves, absorbed the ideas and opinions of others and then accepted it as truth. Then as you tell yourself how bad you are it's even easier to believe because it is now your own voice saying it, so it surely must be true.
It can be a tough process but it is possible to get to a point where you still listen to your own voice but the voice is now you being true to yourself, not just regurgitating the lies that you have been fed. The voice reminds you of your good points and the value you bring to those around you. It tells you that you do make a difference.
It is true that whatever you tell yourself you will believe. So wouldn't it be great to be telling yourself how awesome you are?