A good self confidence arises from a good self esteem. However, many people suffer from a poor self esteem. It stops them from doing the things they like and love.
Know that you can use some simple Law of Attraction confidence boosters to improve your current situation.
Your self esteem defines how you experience yourself in general.
If you have a good self esteem, you mostly see yourself in a positive light. Then again, people with a poor self esteem see themselves as lacking something, miserable, being a failure, and so on.
Self confidence is a state of mind, it's a feeling about what you believe about yourself and how you experience yourself in different situations.
For example, you can be very confident in certain situations like at work, but then again, you can be uncertain in relationships related matters. Or it can be the other way round.
Your self confidence is the result of both your conscious and unconscious practice.
Your environment affects your confidence at the unconscious level. If you happen to experience yourself as a failure, you can start building a good self confidence for yourself. Consciously.
You can choose what you focus on in many things, so your attitude does play an important role in your self confidence. It's important how you experience your identity.
If you experience that you have a poor self esteem, know that you can consciously change that identity into a good self esteem.
When you're ok with yourself, other people can't hurt you in any way. People who deliberately try to hurt others often have poor self esteem themselves.
It's important to feel confident so that you can have the courage to do the things you want and love to do. And often, when you do things that you love, you feel naturally confident.
And no, being confident doesn't mean that you'd be stuck-up.
Most likely, they have been "practicing" it for so long. Mostly unconsciously, though.
Failures in life, such as bad relationships, can make you have poor self esteem. But remember that those things have happened to the person you were back then. That's not the same person you're today.
It's quite useless to spend time on asking why those things happened, because you can't change the past. If you feel like you have to think of the things that happened in your past, then ask yourself better questions like "What have I learned from that experience?"
Always start building your future from this moment onwards.
What people in your environment talk, how the media influences your self esteem... Commercials with beautiful people with perfect bodies have influence on how we think about ourselves. We don't necessarily come to think about that most of those images have been edited in a way or another. Then we may experience ourselves as lacking.
Your self confidence is about how you experience yourself in your mind.
Regardless of the same parents, siblings, school, or anything, even twins can have a totally different picture of themselves. One can have a good self esteem, whereas the other one is very uncertain about himself or herself.
Don't try to hide your uncertainty in different situations. For example, if you're speaking publically, rather admit to your audience that you're feeling a bit uncertain about something. Most likely, it helps you handle the situation better. It makes you feel more confident when you accept yourself as you are.