INTJs love learning. Every INTJ personality description says so. This is the main motivator to keep taking classes even when one has a career.
As I have lived my life after finishing my academic studies, I have realized that I want to keep learning but I don’t want to run out of topics to learn. This has made me consider picking up the taking classes hobby (with logic and purpose) once I get a real job. I don’t necessarily like the academic pressure and subjecting myself to the judging from professors; I do like the learning that occurs in the class.
In the mean time, YouTube and Google will be my go to source to learn stuff (they’re free).