In a corporate environment where a can-do, go-team attitude is important for both personal and team success, it can seem like you must say “yes” to every task thrust your way. Sometimes, in fact, it seems impossible to say “no.” If your manager drops another project on your plate while you’re running out the door, or when an end user asks if you can add just one more little feature while you’re elbow-deep in the code, it’s challenging at best to refuse.

But while it may make you feel anxious to do so, sometimes you have to say “no” to requests—or demands—in order to keep from drowning in overwork and consistently working a 12-hour day. After all, a complete physical and/or emotional breakdown would be bad for your productivity. Even if it’s never happened to you, you’ve seen it in others; and you’ve probably felt the strain when weighed down by almost enough straws to break your back. It happens to anyone with significant responsibility who juggles multiple projects.

When you’re on the ragged edge of using your computer as a boat anchor, something must give. If you learn to say “no” to people just a little bit more, you’ll witness a new feeling of release and relief.

Revenge of the Yes-Man

Years ago, I saw a “Wizard of Id” comic strip that made me laugh. It showed a man in court attire running over the landscape, shouting “No! No! No! No!” over and over. When one soldier asked another, “What’s with him?” his buddy replied, “That’s the king’s Yes-Man. It’s his day off.”

Like the Yes-Man, you must occasionally say no, because it will keep coming until you wave the white flag. Overcommitting and taking on too much work will tangle you up so badly your overall performance will suffer in the end. Believe me, people will take advantage of your good nature if you let them. So when one of your co-workers asks if you can do them just one little favor, check your schedule. If you don’t have enough time, say you regret you don’t have the bandwidth to take it on right now. You don’t have to be snappy about it, but you also don’t need to take everything people hand you.

Don’t put everyone else’s needs over your own. Don’t “volunteer” to coach the company’s Little League Team (do you even coach your own son’s little league game?), or bake a cake for someone’s birthday, or do a quick analysis for the guy in the next cube, no matter how someone pressures you—unless, in the last case, he already has your manager’s backing.

Again, you don’t have to be rude about it; just tell the person you’re fully committed right now. Are you willing to give up family time to do someone else’s work, or stay late because you didn’t get yours done? There’s only so much time in the bank for any particular workweek—and there’s no way to add more, so don’t let someone else overdraw your account.

Here are a few “creative” ways to say no:

1. Offer to meet people halfway. Just tell the person, “I can’t handle this now, but if it can wait two weeks, I can look at it then.” If it’s time-sensitive, you’re off the hook. If not, it can wait until a slot opens in your schedule. Or magically, someone else will be found who can do it.

2. Ask if you can get started and finish later. If you can do a certain amount of the task but can’t get it all, offer to do that much. Do enough to get it started, and they might find someone else to do the rest.

3. Make an introduction. Tell them, “While this isn’t a good fit for me right now, here’s someone who might be able to help,” or “These resources might help you find what you’re looking for,” and direct them accordingly.

4. Punt it. If people ask for your help with a task and you can’t or don’t want to give it, suggest they make the request through your manager. They may be reluctant to do so, and even if they do, your manager might shoot them down. My office manager is often asked by my friends’ assistants to show them how to do something or train them, and she always copies me in, so I can say, “her time is fully committed supporting our business, so I regret we won’t be able to do that for you.” Then give an idea where to get answers.

What If It’s the Boss?

If your direct superior keeps putting more projects onto your overloaded plate, you’ll have to get help prioritizing. Find out the ranking of the tasks in terms of importance and give your estimated dates of completion. Not surprisingly, some managers will reply with a less-than-useful “everything’s top priority.” In other words, nothing is. Discuss a priority framework to guide you, so you make sure to accomplish the top priorities first.

Others may want you to do everything ASAP. Still not very useful. If this is the response, you’ll just have to say, “I’ll work on Project A first, then.” If you get an objection, then ask what you should do instead. Point out you can only do one thing at a time effectively, and ask—again, without rancor—for assistance in prioritizing. There’s no human way you can complete five significant projects all due Friday without something breaking down. Because you’re only flesh and blood, that thing will probably be you.

Don’t let it happen. Even when you can’t say no, find a way to do it anyway. Your productivity and sanity will thank you.

© 2014 Laura Stack. Laura Stack, MBA, is America’s Premier Expert in Productivity™. For over 20 years, Laura has worked with business leaders to execute more efficiently, boost performance, and accelerate results in the workplace. Her company, The Productivity Pro, Inc., provides productivity workshops around the globe to help attendees achieve Maximum Results in Minimum Time®. Laura is the bestselling author of six books, with over 20 foreign editions, published by Random House, Wiley, and Berrett-Koehler, including her newest work, Execution IS the Strategy (March 2014). Widely regarded as one of the leading experts in the field of performance and workplace issues, Laura has been featured on the CBS Early Show, CNN, the Wall Street Journal, and the New York Times. Connect via her website, Facebook, or Twitter.