Be Cool by Joni Mitchell is a jazzy tune that speaks to the importance of staying calm and composed in the face of life's challenges. The song encourages listeners to adopt a laid-back attitude and not to let stressful situations get the better of them. Key themes include relaxation, stress management, and emotional resilience. Particularly poignant moments in the song are when Mitchell advises to 'Keep your cool' and stresses that worrying doesn't change outcomes but maintaining composure can help you navigate through the hard times more effectively.