Today, nearly all my students work -- many of them full-time -- and class attendance and homework are things they squeeze in as long as it doesn't interfere with the rest of their lives. I have received complaints that a mere 10 pages of reading for the next class were too many because the students were so busy. They expect you to provide make-up lectures, exercises, and tests at their convenience. Most drive nice cars, wear the latest fashions, and have both a cell phone and an iPod yet tell me they can't afford a $25 textbook.
I'm amazed how students behave even when they don't mean to be disrespectful. Students who can barely add or put together a coherent sentence pulling out Soduku or crossword puzzles in the middle of a lecture.