Why is it hard for me to say no at work?

There are quite a number of them. Again, let me remind you that doing your fair share and even going overboard once in a while are desirable traits in an employee. Putting in an extra hour here or there, volunteering, or occasionally taking on an odious task that no one wants to do shows initiative, spunk, passion, team spirit, drive, leadership, and commitment to your job. If you do these things for the right reasons, you feel proud of yourself and other people will rightfully admire you and might even view you as a role model. What you want to avoid, however, is earning the label of chump, self-sacrificer, angel, soft touch, or Saint Arlene.