Risk Assessment is perspective

Risk assessment is a personal perspective of things. It's one own state of situational analysis. Imagine you wake up and see clouds in the sky. You may take then lightly and go out without any preparations. Your neighbor might read the situation differently and go out with an umbrella or water proof jacket. In the end, whether it rains or not is another thing. You and your neighbor looked into the skies and read the situation differently and had a different opinion of risks associated with the clouds in the sky.

Same analogy can be applied for IT projects too. Imagine a verification engineer working with a piece of software. His job is to find bugs. So the risks associated with his job is that faulty end product reaches the customer. He will try to list down all the use cases and scenarios that may fail and then based on them make appropriate test cases. Over time when he has done many similar projects, he may become a little complacent as certain scenarios never trigger any bug. He may stop running those scenarios in the test regression suite.

If a new verification engineer is hired, he may have a different perception of risks associated with the same software. He may employ more corner cases to test more thoroughly.
In the end, both engineers may or may not be able to find bugs but one thing is for sure that both had a personal perspective to the risks associated.