[martin_ky]

In addition to what has been said in this thread about office culture, politics, internal processes, etc. I believe a big factor in reducing work-related stress in any job, is actually being competent at your job.

What I mean is, work in a domain you know something about, with tools and technologies you know well. Be comfortable with your skills and know they are on par with the task you've been given (and also know when they are not). Don't put more on your plate than you can take.

Of course, being too comfortable can result in stagnation. Sometimes, we need to push ourselves or be pushed in order to learn and grow. Let your superiors know when a task is outside your comfort zone. A good mentor will try to push you, but also let you fail gracefully.