Dieter Zapf knows a lot about competition for positions, intrigue and bullying.

He was one of the first scientists to study mental stress in the workplace.

For decades he has advised those affected and companies.

The professor for work and organizational psychology at the University of Frankfurt explains why lunch with colleagues can be worth its weight in gold.

WORLD:

Are there people who are simply too sensitive to have a career?

Dieter Zapf:

Classic conflict avoiders have a hard time in any case.

As a manager you always have to assert yourself against others.

There is competition for certain positions, disagreement on factual issues.

You need a reasonably thick skin.