Some people definitely do fixate (and derive a sense of purpose, whether that's good or not) from perpetual productivity improvement – I think this is why online productivity and life hack gurus are so popular.

But for some, it's all about looking like they care about productivity because that's what their job or manager expects. Certainly this was the case for me. Throughout my twenties, I pushed myself to be more "productive" in my career because I thought I had to look like a go-getter to the people who paid me. I put in extra hours and effort, and even enrolled in an online university course to further expand my skills (resulting in me having next to zero free time!).

I still like to work hard and do good work, but I no longer push myself to be very good at everything I do. "Competent" is my aim. Doing my paid work to a standard that is "good enough" is not only easier on my stress levels, but my managers continue to report satisfaction with my work.