Not confident? Blame your parents. As this video from The School of Life explains, men tend to have low self-esteem if they think their dads have achieved more than them. Same goes for women and their moms. (Yet we never see Father's Day cards that read, "Thanks, Dad, for being so successful! Now I have cripplingly low self-esteem.") Comparing ourselves to our friends doesn't help either. But this isn't license to say, "Woe is me!" Focus more on the amazing things you're doing (not what others are achieving)—it'll do wonders for your self-esteem.

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