Yawn. The reader looks at your story and says “so what?” I can make this mistake when I get so excited about the plot or the plot twist that I forget about the players.
What went wrong? We forgot to tell a story. A description is not the same as a story. In a story that lacks emotional resonance, the reader has nothing to look forward to except the assimilation of mildly interesting data. A story is essentially a peek into one or more relationships, even if the only relationship is the main character’s relationship with themselves or with their environment.
What is the motivation for your character’s actions? Why do they care? When the reader knows how the characters feel, and why, they are more likely to empathize, to walk the journey with them and to care what happens to them.
So, don't be afraid to feel what your characters are feeling and to share that with your audience. Your readers will thank you for it.