A word you hear a lot these days is “oversubscribed.” It’s got nothing to do with magazines — who has time to read when you’re working all the time? Being oversubscribed means taking on too many tasks at once, and as Lily Herman, co-founder of the lifestyle website the Prospect, writes in a recent post for the Daily Muse, this is a natural impulse. No one wants to be seen as lazy, and hey, if you can score points with your boss by juggling five things at once, why not give it a shot?

There are lots of reasons why not, and in a post titled “3 Powerful Reasons to Say ‘No’ to Your Boss and Coworkers,” Herman shares a trio of pretty compelling ones. Read on and learn to embrace a certain two-letter word.

1. It Leaves Time for the Good Stuff — When you take on a project you’re not really interested in, you’ll cut into the finite number of hours you have to devote to your job. That means less time for the projects you actually care about. It’s one thing to wow the bosses with your willingness to help out as needed, but wouldn’t you rather blow everyone away with your excellent efforts on tasks more closely aligned with your career goals and interests?

2. You’ll Avoid Burnout — Every now and then, you’ve got to look out for No. 1. That’s you — not the CEO or head of your department. As Herman writes, she recently opted out of a work event to stay home, watch a favorite TV show, and hit the hay early. She felt refreshed the next day, and for that reason, she made the right call.¬†According to Kristin Muhlner, CEO of NewBrand Analytics, you’ve got to show “ruthless discipline” when it comes to only doing things that leave you feeling fulfilled and happy.

3. You’ll Show That Your Time Matters — Saying “no” sends a clear message: My time is valuable. No one likes a doormat, and you don’t want to be the type of employee that the higher-ups think they go to when any little nagging project needs completion. It’s better that they see you as someone who prioritizes and takes pride in your work. Then, they’ll come to you only when they’ve assessed the situation and determined that you’re the perfect person for the job.