False Friend: “Rollercoaster of Emotions”: While a situation that is
一波三折 will likely cause a rollercoaster of emotions, the idiom itself describes the external events, not your internal feelings. It focuses on the plot, not the emotional reaction to it. To talk about feelings, you would use a different term like
心情起伏不定 (xīnqíng qǐfú bùdìng).