There's a problem at universities across the country--longtime tenured full professors you can't get rid of or even reprimand because they're beyond reproach. Hey once they're tenured it takes damn near an act of Congress to give them the boot. These jerks get to a point in their careers where they're flying high and set for life and could care less. They don't grade homework on time, don't email their students back, don't attend important meetings, and generally blow off their responsibilities because well--they can. Sometimes their students futures hang in the balance but do they care? No. Perhaps it makes them feel important to make others wait on them!
And in most cases there's not a damn thing you can do about it. So if you come into contact with a professor like this during the course of your education, turn around and run the other way.