The importance of an excellent professor/instructor who loves the topic and can teach it is huge. Teachers who can successfully convey the learning of the concepts of mathematical formulas goes a long way for students to comprehend and enjoy the material. Students often fail or drop those courses often because the instructor simply sucks at teaching.
This means that today's techies have to learn stuff pretty much for themselves, ironically making them tougher and better disciplined people.
One must admire the grit of these foreign grad students, too. Mastering technical subjects without any knowledge of or cognizance of the Western canon and languages from which they spring is mighty tough. Too gd many of them here, though/