Trying to get kids to be interested in math is a tough sell! We'd like to think that because they are supposed to study and behave properly in school that they will–it might be wishful thinking. Perhaps the trick is to take advantage of what we do know about students (teenagers, at least) –that whatever we ask them to do has to appeal to them on some level.
Maybe we can make it fun. Maybe we need to create a personal reward for evidence of effort (not bribery, of course). Maybe we need to find out what they perceive as valued and valuable and present our learning objectives and techniques so they WANT them.
Is that impossible? No, but it's not easy if we restrict our focus upon what WE adults want instead of what THEY want. Check out the following video link (10.5 minutes) Inertia and notice that these kids have talents and find joy in what they can do well.
The moral is: kids will do what we want them to (and what's good for them) IF they feel successful and proud of their effort (like these kids in the video). If math is a "downer" because students constantly feel inadequate or bored, it's up to us to instill a can-do attitude of success and relevance. And, we can, gol darnit!!!