Something either you have or you dont. You can have low or high self esteem depending on how you were brought up or life experiences you have. If someones praised or thought highly of they will have high self esteem. If they are bullied they will have low self esteem if they dont have a good sense of self.
1. John has high self esteem cause he was encouraged and has faith in himself.
2. Sonny has low self esteem because the girl he was with was embarrassed of his looks and lack of personality.