My professor in university level art refused to teach us how to draw particular things . He explained that if he did then he would just be projecting his own technique and style onto us and we would never actually learn how to draw . Instead we would only learn how to draw a tree . Instead he taught us the process of drawing . What it meant to understand 3 D space and project it onto a 2 D surface . What things like contour and contrast meant . And allowed us to draw a tree however we saw fit . However he did push us to refine and improve our technique as time went by and if we made changes in how we approached things we had to be able to explain why . For me i had learned to draw the standard way by drawing under drawings of basic shapes but he pushed me to cut loose a bit and just draw gesture and form without consideration to accuracy and HOLY SHIT did it have massive impacts when i put the two together . He did show us how he draws a tree though . However he also made sure to show us how other artists draw trees and that the method is just as much an important part of the artistic process as the end result . Take my cousin for example . Once she took an art class at some event where she learned how to draw an Eye . Now let me tell you , now she can draw an Amazing eye but thats it . If you asked her to draw a foot ? Nope . No way in hell . My classmates and I ? Well now we can draw anything pretty well , and with time hopefully really well . But then again your teacher might have just been lazy .