My chemistry teacher isn't the greatest. She gives us all these sheets of work we're supposed to do, but she tells us right from the beginning she will never check them, and says she knows most kids will just blow them off and not do them. Not that you miss much by not doing them, or by not reading the textbook, most material in the class is repeated so many times there is no way to not learn it no matter how stubbornly you're ignoring the work. Also we'll have review days in class where we go over the answers to the worksheets, and the teacher then gets pissed off no one did them, despite admitting when she gave us the sheets that she knew most students wouldn't do them. She'll then spend 10 to 15 minutes ranting about our work habits, and practically nothing will get done.
EDIT: But my world history teacher is far worse. While we still learn the material in chem, and it's overall a pretty fun class, my world history teacher is the epitome of incompetence. He does not give the impression he knows the materials at all, giving lectures where he just reads the textbook out loud in a bored, monotone voice. He expects us to take notes on these lectures, but he never actually reads the notes. To test his boundaries, one time I just wrote song lyrics down, no actual notes, and I still got full credit. He will also give us packets on sections from the textbook. These packets can range from 5 to 20 pages, but they're always worth the same number of points. He also never notices if people tear one or two pages out of the packets, which of course almost everyone does. These packets will also often have extra credit in them. The value of this extra credit is often more than half the packet's worth, sometimes equal to the packet's worth, and you still get extra credit even if you don't do the packet. What are most people going to do in this situation, do the 20 page packet for 50 points, or do the one page of extra credit for 50 points? For late work, if you don't write the word "late" on the sheet when you turn it in, he'll almost never notice it was turned in late. The punishment for turning something in late is you lose half the worth of the packet, but he doesn't remove points from the extra credit. Say you have a 50 point packet with 30 points extra credit, and you turn it in late. You still get more than 100%, because half the 50 is 25, plus the 30 extra credit, gives you 55/50, or 110% credit. If you're smart, do all the work and all the extra credit, you can basically skip the final and still have an A.