Saying no is an option! We can give you some ideas as to why you are struggling with this, and some options to deal with it, but ultimately you're the only one who knows why you 'won't' say no. (I try to avoid the word 'can't' when it isn't accurate, because phrasing things like that can already put us in a negative mindset.) So why might someone have a hard time saying no to their boss, even under extreme circumstances? Is there something you're afraid of? What consequences are you worried or anxious about, and how realistic are those consequences, and how survivable are those consequences? The thing about fears and anxieties are they do not often account for all the awesome things you have already done or have to look forward to. We rarely worry that good things will happen. Some fears and anxieties that keep people from saying no at work are: not being seen as a team player or carrying their fair share, facing repurcussions like a hard talking to or worse, &c. But what about the benefits of saying no? Some bosses will respect you for it, it shows that you know your limitations and are firm on your boundaries, which are both respectable things, it shows that you are already giving your all to the company, which is a great work ethic, not to mention less stress and strain on you which means a healthier and happier employee. So what can you do about this? Instead of an outright 'no', consider some alternatives like compromises - you will do (a) but not (b), or you will do the extra work but at a time of your choosing, or say you understand the importance of the extra work but would like to refer it to another employee so you can focus on the equally important work you have on your plate. Sometimes we hvae to put our foot down and it is a sign of strength. Social anxiety can definitely interfere with this, but the more work we take on that we cannot handle, the more frustrated, stressed, and unhappy we might become. Personally, I feel for your situation because I am often overworked; I have said things to my boss like, "Choose one of these things because it is inhumanly possible for any one person to do both right now" and "I will do the extra thing next week if that works for you" or "In order to complete this when you want, I have to delay this other project. Is that okay with you?" I have even requested private meetings with my boss in which I have itemized every project I have been working on in the past month, so they can see how busy I have been. These things make the conversation about your desire to complete the work eventually, without making it seem like you are a negative employee. My bosses have respected me for standing my ground and I am happy to say that over time my workload has evened out and is not so stressful anymore. The same thing can be possible for you! If your boss threatens you or makes you uncomfortable, it is 100% okay to seek other employment (while still employed at this company). Good luck!