Trying to work through a disagreement with a co-worker can be frustrating. However, in most cases if it is too difficult to approach her or we have reached an impasse, we can go to a third party like HR or our boss to help us straighten it out.

But what do we do when we have a problem with our boss? For significant, negative situations like sexual harassment or hostile work environment the path is usually clear: talk to HR, another person in leadership or an attorney.

Yet how can we approach less weighty issues that still need to be addressed? Here are ways to approach saying no to the boss.

He's wrong

Anyone who has led a project, team or organization knows that mistakes happen. And in almost every case, we would all choose to know we were making the mistake before it was too late. Thus, when the boss is wrong, it can be helpful to consider the last time we made a mistake and what happened.

Specifically, if someone was going to inform you of a mistake you made, how would you want it done? As noted in this article by Bernard Marr on LinkedIn, being told tactfully, without blame, in private, as soon as possible and with potential solutions is a pretty ideal way to learn about a mistake.

Then, consider your own thoughts and feelings after being told. Even if the person told you as professionally as possible, would you still blame the messenger? Consider the boss's personality before taking the next step — even a well-planned approach can backfire if the boss is closed-minded or vindictive.

Piling on too much work

Good workers get things done. So, as is often the case, leaders give more work to good workers. Few employees want to let down the boss when she has put so much faith and trust in her work. However, burning out from a huge workload will not help anyone.

Instead, set a meeting with the boss to talk about priorities. Thank her for the confidence she has in your ability to accomplish so much. Then, ask her to help you prioritize using specifics like: "I only have time to do one of these two projects well and on time. How do you want me to approach this?"

Using this approach provides her with a clear picture of the huge workload, timelines and possibly conflicting priorities she has given.

After that, three things could happen. First, she could clearly and simply give you a straight answer about which to do. Second, she could say to do both and acknowledge that she understands the difficulty of the challenge. Both cases provide clarity and pave the way for future positive communication on the subject.

She could, however, take the third option: be mean and use it against you. And if that was already an underlying assumption about the situation, then her answer will certainly confirm it for you. In that case, consider whether it is still worth it to work so hard for someone who does not appreciate your contribution.

The bottom line: Saying no to the boss is not easy and can create challenges. It is important to understand the difference between fear of the worst-case scenario and the fear of having an honest, difficult conversation with the boss.

With that understanding, think through the options and pick the battles that are most likely to have a positive impact.