The stability of emotion differs with different persons. Think about the people around you. Some people usually have nervous moods like a roller coaster, an intense experience, while others have a small varying range, relaxed and peaceful. We might say that one person often feels tense, with strong fluctuation of emotions, while another remains generally calm and maintains a stable mood. So what does science say about which way of feeling is better? Research finds that the secret of happiness is of a mild contentment. True happiness isn't found in extreme highs like moments of euphoria or very Iow lows. Instead, it comes from a mild mood, a gentle sense of satisfaction that stays with us over time. That brings us to a very useful idea: You should find a point of balance and the ideal mood is moderate strain and contentment. Let's break this idea down into two parts. First, moderate strain is not the same as harmful stress. It's the kind of positive tension that helps us focus, learn, and grow. Without any challenge, we might feel too loose, without direction. Second, this is balanced by contentment a calm and grateful attitude toward everyday life. This isn't about big exciting moments; it's the ability to appreciate small good things, which helps reduce major fluctuation of emotions. So, whether you're naturally more like a roller coaster or more like a quiet lake, you can learn to find your balance.