I think “praise” and “challenging work” are connected. If people are not stimulated they will not be motivated to work on the said project and there will be no praise. I think the take away is that people want to work on “challenging work” that gives them stimulation and that they can get excited about. I believe that if you are not challenged, then it is a good time to start looking for employment elsewhere. If a company wants to keep it’s employees and stay competitive, I would think they would want their employees to work on “challenging work”.