I've found very recently that students who are ready to quit or who are questioning the curriculum/ program sometimes just need a little bit more encouragement. I have one student who has been ostracized from the class because he is strange... and yes, he is definitely strange (he has some very odd behavioral habits and often makes odd remarks). After a little while, this student began complaining and holding up class by criticizing the material. I got angry at first. He was so difficult. I thought about it though, and went in a few days later with a brand new approach. I made a joke between him and I. This joke is something that the whole class can laugh at, but that really is a joke between him and I. The other students laugh 'with us' not 'at him'. He doesn't feel the joke is about him, and it definitely isn't as I would never make fun of a student. It also puts attention on him that somehow unites him with the class, and it lightens the mood when things get a bit too serious. I'm new at this, and was really surprised when this worked. I'm always watching to make sure it doesn't become something that upsets him. It hasn't, and he's turned around in attitude and in his confidence.