What you said is actually very reasonable. When you are happy, listen to the concert and remember its melody. Even sad music will not be sad, but it will feel very beautiful. However, listening to sad music when you are sad, such as listening to sad music when you are lovelorn, makes it seem that every sentence of its lyrics is heart-wrenching, as if accusing yourself of losing what you love. Of course, it is a good thing to listen when you are happy, and we should try our best to get out when you are sad. Don't indulge in the music of injury for too long.