I'm taking this class right now where the professor "assigns" homework that's neither collected nor graded.  It's optional, but he strongly recommends doing it because it's the only way we'll learn how to do the problems.  He hands out answers, but not solutions, so we actually have to do the problems and learn things.  It's actually kind of a good way to run a class.  But since no learning happens in class and the book is painfully inadequate, he encourages his students to come see him to ask him questions about the homeworks.  He says to struggle with the problems for a while, and when we get nowhere, go see him. 

The thing with struggling with schoolwork is that I have a pretty low tolerance for it.  There are two possible outcomes:  Either I can (a) struggle with a problem for hours and hours and at some point actually get an answer, or (b) struggle for a little while to no avail and go see the professor.  The problem with the first outcome is that it's really stupid.  If I finally get an answer to a homework problem after two hours of struggling, the reward is hardly worth the effort.  In fact, it's not worth the effort at all in this case, because the homework is neither collected nor graded.  So the only logical option is to go see the professor.  It's a simple concept:  If I have a fixed number of assets (a book, some notes, my cranium), I can only get so far with homework problems before I either hit a brick wall or get the right answer.  No amount of time or effort will allow me to get past that brick wall.  It's like creating something from nothing; there needs to be some sort of outside force.  I need to introduce more assets, such as the professor.  And that's exactly what I do.