Whats the deal with professors?

Have you ever experienced that boredom that comes from sitting in the class, waiting for it to start... and waiting.  They expect that you are on time, which is reasonable, but why don't they feel so compelled.  They think because you aren't seated and waiting, they have every right to come in at the time they decide.  But better yet, they don't come at all.  There is no sickness, they just decided not to tell you that they would be leaving the state.  They expect you to still show up, however, despite the fact that a few hours of sleep would actually help you.  Why don't they have the same policy for themselves- missing school is never acceptable unless you are dying or in labor.  But yet, they don't think like that- superiority must be great.  I can't wait.