No matter how stellar the course design is, no matter how pedagogically brilliant the in- or out-of-class assignments are, no matter how well your carrots and sticks are set up to reward or discourage given behaviors, in the end you are still ultimately powerless to make change happen. There is no magic assignment structure, no perfect metaphor (and God knows I’ve tried thousands), no enlightenment-guaranteed koan that will make every student go “Oh! NOW I get it!”
… I don’t mean to say that no student will be motivated by your efforts — you will undoubtedly catch the ones who are really genuinely interested in learning. But it’s important to accept that there is no way to craft a net that will catch 100% of the fish. They are more interested in escaping than you ever could be in catching them.