I work in a small team of five, where each of us often leads projects in our own field. Recently, my coworker Anna suffered a tragic miscarriage at six months and had to take two weeks off to recover. While she was away, our manager asked who could handle her workload since the project deadline was near. I was the only one trained to do it.

But I refused. I had already covered for another colleague just the month before and was mentally drained. My boss wasn’t happy, but he didn’t force me. As the project started falling behind, the rest of the team grew frustrated and eventually blamed me for not stepping up.

What they don’t know is that Anna and I have a complicated history. Last year, when my mom was hospitalized, I had to take time off, and Anna covered for me. But instead of supporting me, she later told our manager that I lied about my mom being sick just to avoid responsibility for a project she ended up missing.

When I came back, Anna acted as if nothing had happened, but I never forgot her betrayal. So when she needed help, I couldn’t bring myself to do it. I know the project will likely fail, just like mine did back then—but this time, I don’t feel guilty. I don’t believe I should save someone who once tried to destroy my credibility.