Definitions: (1) showing calm courage; (2) possessing the power of endurance or control; bold

Too Far: presumptuous audacity

• Nerves and butterflies are fine – they’re a physical sign that you’re mentally ready and eager. You have to get the butterflies to fly in formation. — Stephen George Bull (1965-) English footballer
• Laugh at yourself, but don’t ever aim your doubt at yourself. Be bold. When you embark for strange places, don’t leave any of yourself safely on shore. Have the nerve to go into unexplored territory. —  Alan Alda [born Alphonso Joseph D’Abruzzo] (1936-) American actor