One of the biggest problems I find with teaching low level classes is that the kids believe that they are stupid. They feel they can't learn so why bother trying. A girl told me today that math has always been her worst subject, she never passes so she feels trying just wastes her time. (The girl is Chinese--so much for the Asian stereotype in math!)
A teacher's job is made harder by the preconceived ideas these kids have about themselves. Before I can get them to learn anything, I have to get them to believe in themselves, to believe that they can, kind of like "The Little Engine That Could" Believing in themselves is half the battle.