> Compare Lincoln’s life with that of John Quincy Adams. Great expectations inspired, pursued, and haunted Adams, depriving him, at critical moments, of common sense. Overestimations by others—which he then magnified—placed objectives beyond his reach: only self-demotion brought late-life satisfaction. No expectations lured Lincoln apart from those he set for himself: he started small, rose slowly, and only when ready reached for the top. His ambitions grew as his opportunities expanded, but he kept both within his circumstances. He sought to be underestimated.
The point -- being too ambitious can slow you down if you're not strategic.