Low self esteem. I was like that while I was growing up. All through my childhood I was told, "Don't do that. People will laugh at you." It was made to sound as though being laughed at was a cause for embarrassment.
Eventually I met a girl who taught me to laugh at myself and I've been leading the laughter ever since.
If your question is about yourself then that's the solution. Stop taking yourself so seriously. Learn to laugh when you stuff up (we all stuff up sometimes). It'll turn your life around.
Because ALOT of other people lack confidence. Therefore your going to feel that rejection inflicted upon your own life self. You can change that. It will not be ALL the time feeling good. You have to work your way to Happiness. It doesnt come, and you just get it. You should try and always act and feel and be confident. No matter what. Theres always people slouching down, trying to hide and masking who they are being there afraid. Don't be that. Just be confident, its easy. There will always be this feeling just act courageously. Step out, if nobody laughs or think its cool who cares...Do it for yourself.