I think it depends on the anger. In the workplace, most anger is best left out of it, but some can be helpful. It can show your passion for whatever it is and prove that you take an interest in it. Of course, I don't mean losing your temper- that's bad news.

This woman's fear was irrational and stupid. What seems odd to me is that someone who is comfortable in their job performance shouldn't be worried about losing their job, unless the boss just has it out for them.