Taking pleasure in someone else’s misfortune is read as a hidden rivalry or an unhealed slight surfacing. Dreams let such feelings show without judgement so they can be understood.
Has this come up in your dreams before? What was going on in your life then?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.