I’ve found the same thing at my job as a software developer, as well as on my hobby projects—including a programming language, which is very like Ph.D. territor

I’ve found the same thing at my job as a software developer, as well as on my hobby projects—including a programming language, which is very like Ph.D. territory. Sometimes the time and code flow easily, sometimes not; forcing myself to work when I’m not in a good state of mind to be productive is actively harmful to my holistic productivity.