My best friend is the one who brings out the best in me.

The line defines friendship in functional, character-centered terms: a “best friend” is not primarily the most entertaining, loyal, or long-standing companion, but the person whose presence and influence elicit one’s highest capacities—integrity, effort, courage, or generosity. It implies that relationships are formative and that we should judge them by the kind of self they help us become. The wording also shifts attention from what a friend does for us materially to what they draw out of us morally and psychologically, suggesting an aspirational model of companionship grounded in mutual improvement rather than convenience or flattery.