Besides the fear of regret, what makes it hard to cut someone off is often the emotional attachment and shared history. When you've invested time and emotions into a relationship, whether it's a friendship or something more, it's challenging to let go. There's also the hope that things might improve or that the person will change. Additionally, there might be feelings of guilt or responsibility, especially if you care deeply about the person and don't want to hurt them. All these factors can make the decision to cut someone off much more difficult.