It’s frustrating when you’re asked to take care of tasks that you aren’t actually responsible for — especially if it happens often.

But say “It’s not my job” a few times and aside from the risk of being terminated, you’re also putting yourself at risk for becoming a mediocre worker.

Once this mindset is implemented in your head, it’ll be hard to change the way you do things in the future. You’ve created a habit for yourself.

You’ll never put yourself outside of your comfort zone at work, because you never take on responsibilities that are essentially not yours. And you’ll never achieve long-term success, writes Erika Andersen in Forbes:
Eventually, your career goals will diminish and all of your jobs will be just that — jobs.

Andersen writes:

“The folks who embrace challenge – say yes to taking on new responsibilities, take advantage of chances to improve their skills, volunteer for start-up projects – tend to build more viable careers. They’re seen as focusing on mutual benefit; on wanting to help the company while improving themselves. That’s the kind of employee that companies want to keep and groom for bigger things.”

In her post, Andersen cites Dan Pink’s book “Drive: The Surprising Truth About What Motivates Us” as saying that one of the most important things people want in their careers is “mastery,” or continuously learning and getting better at what you do.

If you don’t have a need for that and all you actually want is to be able to get your job done as quickly as possible, Andersen says “you might be getting in the way of both your success and your enjoyment.”