A Math comic that only Math majors will understand

This is really a comic that Math Majors will empathize with...

It is probably due to lazy textbook authors who leave almost everything as an exercise, and every other theorem is "trivial". Such a textbook is of very little pedagogical value.

On the other hand, an example of a good Math Textbook is Abstract Algebra, 3rd Edition by Dummit and Foote. It is one of the most widely acclaimed textbooks for Abstract Algebra, one of the most arcane and esoteric fields of Math. I have also written a book review on  Topology by James R. Munkres, another excellent Math book.