It's an abstract conception but an important element of success. Simply to say, it's a positive attitude of everything you practice. Like being a leader, if he has no confidence, how can he head for his group? How can he let his team members trust him? Though we absolutely know its importance of life, sometimes we still are in depression. Therefore, we need the enough ability to encourage ourselves as well as the concern and back from our family and friends.
The another condition is someone excessively be proud of theirselves. They could show off much over by theirselves. Everyone at least has one or more achievements exposed out to improve their confidence. Before I was always jealous others' good side. Why I should do that unuseful for me? Be confident, why not become the person been envy from others? I also can do best myself.