When you are taking a new course/learning a new thing what keeps you motivated to continue learning new things? Is it pure curiosity or the fact that you need t

When you are taking a new course/learning a new thing what keeps you motivated to continue learning new things? Is it pure curiosity or the fact that you need to learn something to get the job done? In e-mail based courses I like the fact that I get new content that I should learn until next e-mail. This reminds me od deadlines in Coursera based courses and this creates some kind of obligation in my mind that I try to fulfil.